It’s a Tang!! It Looks Just Like Me! Attack!

BRS

AKL1950

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 12, 2022
Messages
420
Reaction score
401
Review score
+0 /0 /-0
Location
The Villages
Okay, I’m not a scientist, marine biologist or someone who has been doing aquariums for 50 years. But, I do sometimes question what I read. When something doesn’t make sense, I go looking for the WHY it doesn’t. This is one of those times. Hope this doesn’t offend anyone, and makes a few laugh in the process. Here goes:

Can’t count the number of times I have read threads here, and elsewhere, where it is said that if a Tang sees another that looks like it, then it will be aggressive toward that fish. Hum?? Let me think about this. The question that comes to mind would be; how does a Tang, or any other fish for that matter, that lives in the ocean, or aquarium, actually know what they look like themselves? Well…..maybe there are little reef area restrooms where they can go in and look at themselves in the mirror. No, probably not. Don’t think they would remember what their parents looked like. Guess their best friend could describe how they look to others. No no, that can’t be it. They can see their reflection in another fishes eye. No, no? I think the answer is, fish have no idea what they look like themselves. So, saying if it sees another that looks like it, it will be aggressive toward that fish just doesn’t seem to wash.

So, where did this wive’s tale get started? Well, that could take years to figure out. It will be easier to determine why it got started. I believe it got started, because that’s what “we” see. Not what the fish sees.

Yes it’s true, if a tang sees another new fish that “looks” exactly the same, or similar, in most cases it will be aggressive toward that fish. But why. Fish don’t know what they look like themselves, so what is it? The simple answer is smell. We humans are one of the few species on this planet that use sight as our primary sense. Most other species use smell. We use it to some extent. If we smell a skunk, we know one is close and become more vigilant. But we usually rely on sight. Most species use smell to identify themselves and to use smells of others to identify them as friends or foes. Our little fish friends do it well, and have to because the water may not always be pristine clean. All species, including us, release scents known as pheromones. A simple definition is “A pheromone is a chemical that an animal produces which changes the behavior of another animal of the same species”. Fish, along with all other species, use this and other means such as urine, feces and body sweat to identify themselves, others, mark territories, warn off competitors or attract mates.

Fish (especially tangs) are aggressive for three reasons. Territory, food and mating (basic essentials of survival). There are a few that are genetically predisposed to display hyper aggression, but that’s another topic. So the answer is, “when a Tang sees another that looks exactly like it, it will be aggressive toward that fish” should be changed to “when a Tang senses another Tang, usually of the same species (through identification of pheromones), it will become more aggressive toward that fish because it activates the Tang’s basic survival instincts. Interesting note, pheromones are also used to identify siblings. Those fish which are siblings would probably not be aggressive toward each other. Tangs, and other fish can also be aggressive toward unrelated species. That goes back to the basic instincts of territory, food and mating rights. Or, I guess you could say the easy answer is, they just don’t like the way they smell.

Now, I know someone is going to say, well when you put a mirror in front of it, it becomes aggressive and can’t smell the mirror image. Ah, true. But ask yourself why that happens. Imagine. Tang approaches mirror to examine the new fish. Mirror image swims toward Tang. Tang stares at mirror image. Mirror image stares back. Tang makes a jester of dominance by flaring fins. Mirror image does the same. Well, in my world as a fighter pilot, it would be time to say “fights on, fights on” because no one is backing off. Tang and it’s reflection both attack. Now, as time goes by, the Tang stops flaring at the image and the image stops flaring back. No more aggression. Time to remove the mirror. The Tang is not attacking its reflection, it’s attacking another fish that displayed similar aggressive moves. Pretty much identical moves.

So, okay, I’ve stopped running around in tight little circles. Remember, this little episode was only about fish knowing what they look like. All the other instinctual aggression reasons are still in play. Since we all (most all) love our Tangs, I hope this will help a little in understanding their predisposition. They can’t help themselves because basic genetic survival instincts are hard wired in them and they have a hard time over coming it. Guess It would be like a Tiger letting another unrelated Tiger share its domain. Probable won’t happen without a lot of pain, caring and understanding. But, we will keep trying, because that’s who we are.

Jetson
 
AS
Aquarium Specialty - dry goods & marine livestock

Mibu

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Oct 17, 2020
Messages
11,766
Reaction score
34,789
Review score
+0 /0 /-0
Location
Illinios
@Lasse has a very interesting method of introducing fish to his display. I believe he puts them in the sumps so the fish have time to "smell" the soon to be added fish. Apparently, this works well for him, and reducing aggression.
 

Jedi1199

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Jan 16, 2021
Messages
4,110
Reaction score
9,174
Review score
+0 /0 /-0
Location
Mecred, CA.
Pretty sure all animals know what their species look like instinctively other wise tigers would be trying to mate with a zebra instead of eating it. Comes down to the second most important thing in the animal kingdom after food, making babies.

Not sure that analogy applies. Cats are extremely intelligent. In an upper species such as this I believe it is likely a combination of both smell and sight. For a lower species like a fish, the pheromone conclusion makes sense actually. I am sure they use sight to identify food, but in the discussion presented here, the conclusion makes more sense than most other options.
 

Jedi1199

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Jan 16, 2021
Messages
4,110
Reaction score
9,174
Review score
+0 /0 /-0
Location
Mecred, CA.
@Lasse has a very interesting method of introducing fish to his display. I believe he puts them in the sumps so the fish have time to "smell" the soon to be added fish. Apparently, this works well for him, and reducing aggression.

Hmmmm... that is interesting!! I may have to try that once I get the new tank running.
 

zdrc

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Feb 21, 2022
Messages
179
Reaction score
156
Review score
+0 /0 /-0
Location
USA
Doesn't make sense. Your explanation for the mirror isn't that convincing. It makes more sense that most animals need to innately know what others of the same species look like. Without that they would be at a significant evolutionary disadvantage. Pretty sure it's a combination of smell and sight.
 

Mibu

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Oct 17, 2020
Messages
11,766
Reaction score
34,789
Review score
+0 /0 /-0
Location
Illinios
Doesn't make sense. Your explanation for the mirror isn't that convincing. It makes more sense that most animals need to innately know what others of the same species look like. Without that they would be at a significant evolutionary disadvantage. Pretty sure it's a combination of smell and sight.
It makes perfect sense. I have to use the mirror trick on my scopas tang when introducing fish. There is a lot of fin flickering, darting and flashing before the attack takes place. Not the reflection or the actual tang backs down.

In my aquarium, Scopas flashes fins, my wrasse bites him/her. Fin flickering over.
 
Top Shelf Aquatics

blaxsun

10K Club member
Review score
+0 /0 /-0
View Badges
Joined
Dec 15, 2020
Messages
16,956
Reaction score
20,100
Review score
+0 /0 /-0
Location
The Abyss
I'm going to offer another explanation for the mirror: tangs are stupid. When I hang one on the side of the tank only a handful of fish actually pay attention (including the sailfin tang, bicolor cleaner wrasse and quoy's parrotfish).

I've got a new circus tang that spent the better part of yesterday schooling with all the other chromis. Why? Why not I say!
 
Tidal Gardens

The_ReefB0y_FOX24

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Jun 15, 2022
Messages
403
Reaction score
278
Review score
+0 /0 /-0
Location
USA
Great read funny and makes plenty of sense.
Disgusted Feet GIF by AFV Babies
 

ReefLife_Guy

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Apr 6, 2022
Messages
337
Reaction score
466
Review score
+0 /0 /-0
Location
Birmingham, AL
Interesting perspective but "smell" or chemoreception is not the simple answer here. I would argue visual cues are a major factor in interspecies and intraspecies aggression seen in home aquariums, at least in the short-term when decision for fight or flight is necessary. If this was not the case, then experts in the hobby would not recommend adding new tankmates to a tank when the lights are off. If it was mainly dependent on chemoreception, then poor visibility (via turning the lights off) would have no effect on mitigating aggression. Typically diurnal fish with good eyesight rely on their sense of sight first and other senses secondarily but this is dependent on species and the behavior relying on the sense. In the case of a tang who immediately displays aggression, it is from the sight of the fish and not the "smell". In the case where a tang who normally has no issues with other tankmates suddenly displays aggression toward another fish in the tank, then I would say it was more likely triggered by some other sense assuming nothing else has changed in the tank from the aquarists perspective. This could be for a multitude of reasons like you mentioned sexual maturity or even sometimes fish can sense disease in other fish and will attack them for that reason.

Yes it’s true, if a tang sees another new fish that “looks” exactly the same, or similar, in most cases it will be aggressive toward that fish. But why. Fish don’t know what they look like themselves, so what is it? The simple answer is smell.

I think you might be giving too much credit to the intellect of a fish. When we say that they are aggressive toward fish that "look" similar, we don't assume the fish has a sense of self in the way that we have a sense of self. Fish use visual cues based on evolved instincts to know how to react to something they see. For instance, they may use smell to find food but they use their sight to decide whether they can actually eat that food. This decision is based on many factors but a few visual ones would be like size, shape, movement patterns, and color (to an extent, because colors are distorted underwater). While a yellow tang may not know that it is a 3 inch, laterally compressed, yellow fish, they do understand relativity. There are so many factors that go into whether a fish attacks something but I don't think it is as simple as just "smell". Ask my royal gramma who attacks my algae scraper every time I'm cleaning the glass. He doesn't attack it when it is just still in the tank, even when it is in his claimed "territory" but the moment I start making slow jerking movements with it he suddenly goes after it striking multiple times around the tank. In this case the gramma is responding to movement, shape, and size of the object and not simply "smell".

The whole topic is very complex and nuanced but basic principles known from evolutionary biology and the study of animal behavior can help guide us to make the best possible decisions for our pets. Introducing fish in order of less aggressive species to more aggressive, introducing fish with the lights off, using breeder boxes to introduce fish with already aggressive fish in the tank, changing up the aquascape, etc., are all techniques to manipulate our fish in our favor based on knowing natural tendencies of certain species and observed behaviors in the wild.

Probably the best studies on fish behavior are in zebrafish because they are a very commonly used animal model. I'm sure if someone did some literature searching they could find more data on this but extrapolating conclusions from those studies or even studies in the wild to a home aquarium is probably also difficult.

Good discussion though! I don't think many hobbyists think much about the things they cannot see (like pheromones). It seems pretty common for us to talk about coral behaviors/responses to some of their chemical warfare but people don't often think about this when it comes to fish and how they also use chemoreception in response to the world around them.
 
www.dinkinsaquaticgardens.com

Tamale

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Oct 1, 2021
Messages
141
Reaction score
216
Review score
+0 /0 /-0
Location
United States
Okay, I’m not a scientist, marine biologist or someone who has been doing aquariums for 50 years. But, I do sometimes question what I read. When something doesn’t make sense, I go looking for the WHY it doesn’t. This is one of those times. Hope this doesn’t offend anyone, and makes a few laugh in the process. Here goes:

Can’t count the number of times I have read threads here, and elsewhere, where it is said that if a Tang sees another that looks like it, then it will be aggressive toward that fish. Hum?? Let me think about this. The question that comes to mind would be; how does a Tang, or any other fish for that matter, that lives in the ocean, or aquarium, actually know what they look like themselves? Well…..maybe there are little reef area restrooms where they can go in and look at themselves in the mirror. No, probably not. Don’t think they would remember what their parents looked like. Guess their best friend could describe how they look to others. No no, that can’t be it. They can see their reflection in another fishes eye. No, no? I think the answer is, fish have no idea what they look like themselves. So, saying if it sees another that looks like it, it will be aggressive toward that fish just doesn’t seem to wash.

So, where did this wive’s tale get started? Well, that could take years to figure out. It will be easier to determine why it got started. I believe it got started, because that’s what “we” see. Not what the fish sees.

Yes it’s true, if a tang sees another new fish that “looks” exactly the same, or similar, in most cases it will be aggressive toward that fish. But why. Fish don’t know what they look like themselves, so what is it? The simple answer is smell. We humans are one of the few species on this planet that use sight as our primary sense. Most other species use smell. We use it to some extent. If we smell a skunk, we know one is close and become more vigilant. But we usually rely on sight. Most species use smell to identify themselves and to use smells of others to identify them as friends or foes. Our little fish friends do it well, and have to because the water may not always be pristine clean. All species, including us, release scents known as pheromones. A simple definition is “A pheromone is a chemical that an animal produces which changes the behavior of another animal of the same species”. Fish, along with all other species, use this and other means such as urine, feces and body sweat to identify themselves, others, mark territories, warn off competitors or attract mates.

Fish (especially tangs) are aggressive for three reasons. Territory, food and mating (basic essentials of survival). There are a few that are genetically predisposed to display hyper aggression, but that’s another topic. So the answer is, “when a Tang sees another that looks exactly like it, it will be aggressive toward that fish” should be changed to “when a Tang senses another Tang, usually of the same species (through identification of pheromones), it will become more aggressive toward that fish because it activates the Tang’s basic survival instincts. Interesting note, pheromones are also used to identify siblings. Those fish which are siblings would probably not be aggressive toward each other. Tangs, and other fish can also be aggressive toward unrelated species. That goes back to the basic instincts of territory, food and mating rights. Or, I guess you could say the easy answer is, they just don’t like the way they smell.

Now, I know someone is going to say, well when you put a mirror in front of it, it becomes aggressive and can’t smell the mirror image. Ah, true. But ask yourself why that happens. Imagine. Tang approaches mirror to examine the new fish. Mirror image swims toward Tang. Tang stares at mirror image. Mirror image stares back. Tang makes a jester of dominance by flaring fins. Mirror image does the same. Well, in my world as a fighter pilot, it would be time to say “fights on, fights on” because no one is backing off. Tang and it’s reflection both attack. Now, as time goes by, the Tang stops flaring at the image and the image stops flaring back. No more aggression. Time to remove the mirror. The Tang is not attacking its reflection, it’s attacking another fish that displayed similar aggressive moves. Pretty much identical moves.

So, okay, I’ve stopped running around in tight little circles. Remember, this little episode was only about fish knowing what they look like. All the other instinctual aggression reasons are still in play. Since we all (most all) love our Tangs, I hope this will help a little in understanding their predisposition. They can’t help themselves because basic genetic survival instincts are hard wired in them and they have a hard time over coming it. Guess It would be like a Tiger letting another unrelated Tiger share its domain. Probable won’t happen without a lot of pain, caring and understanding. But, we will keep trying, because that’s who we are.

Jetson
In my experience fights on usually just happens once red and blue are in their respective caps or red has their picture presentation prepped and then call “ready” on the freq. Feel like “tang 1, commit single tang group, b/e” works better
 

ReefLife_Guy

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Apr 6, 2022
Messages
337
Reaction score
466
Review score
+0 /0 /-0
Location
Birmingham, AL
I read this and all I thought was “million dollar idea!” Come up with a calming pheromone to dose when introducing new fish to curb aggression for a little bit till they are all established…..might work, might not, who knows!
They have this for dogs and cats, called adaptil and feliway (if you want to look them up). They come in sprays and wall diffusers :face-with-tears-of-joy: . I will say in my experience a stressed animal does not give a flip what you sprayed on the towel before you brought it back, if that cat wants to rip your jugular out they will do so. Although still probably a million dollar idea but not because it works so well but because people will try anything and if it works for them one time then "it must work for everyone else too"
 
OP
AKL1950

AKL1950

Active Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 12, 2022
Messages
420
Reaction score
401
Review score
+0 /0 /-0
Location
The Villages
Pretty sure all animals know what their species look like instinctively other wise tigers would be trying to mate with a zebra instead of eating it. Comes down to the second most important thing in the animal kingdom after food, making babies.
Let’s assume this happens at night where the Tiger can’t see either. Fairly certain that through smell, that Tiger knows whether it’s food, competition or a mating opportunity. Even in daylight, that tiger may not be able to visually distinguish between a male and female Tiger, but if he can smell it, he will know whether it’s danger or a mating opportunity.


I read this and all I thought was “million dollar idea!” Come up with a calming pheromone to dose when introducing new fish to curb aggression for a little bit till they are all established…..might work, might not, who knows!
I think for us humans it’s called Prince Valium.


Interesting perspective but "smell" or chemoreception is not the simple answer here. I would argue visual cues are a major factor in interspecies and intraspecies aggression seen in home aquariums, at least in the short-term when decision for fight or flight is necessary. If this was not the case, then experts in the hobby would not recommend adding new tankmates to a tank when the lights are off. If it was mainly dependent on chemoreception, then poor visibility (via turning the lights off) would have no effect on mitigating aggression. Typically diurnal fish with good eyesight rely on their sense of sight first and other senses secondarily but this is dependent on species and the behavior relying on the sense. In the case of a tang who immediately displays aggression, it is from the sight of the fish and not the "smell". In the case where a tang who normally has no issues with other tankmates suddenly displays aggression toward another fish in the tank, then I would say it was more likely triggered by some other sense assuming nothing else has changed in the tank from the aquarists perspective. This could be for a multitude of reasons like you mentioned sexual maturity or even sometimes fish can sense disease in other fish and will attack them for that reason.



I think you might be giving too much credit to the intellect of a fish. When we say that they are aggressive toward fish that "look" similar, we don't assume the fish has a sense of self in the way that we have a sense of self. Fish use visual cues based on evolved instincts to know how to react to something they see. For instance, they may use smell to find food but they use their sight to decide whether they can actually eat that food. This decision is based on many factors but a few visual ones would be like size, shape, movement patterns, and color (to an extent, because colors are distorted underwater). While a yellow tang may not know that it is a 3 inch, laterally compressed, yellow fish, they do understand relativity. There are so many factors that go into whether a fish attacks something but I don't think it is as simple as just "smell". Ask my royal gramma who attacks my algae scraper every time I'm cleaning the glass. He doesn't attack it when it is just still in the tank, even when it is in his claimed "territory" but the moment I start making slow jerking movements with it he suddenly goes after it striking multiple times around the tank. In this case the gramma is responding to movement, shape, and size of the object and not simply "smell".

The whole topic is very complex and nuanced but basic principles known from evolutionary biology and the study of animal behavior can help guide us to make the best possible decisions for our pets. Introducing fish in order of less aggressive species to more aggressive, introducing fish with the lights off, using breeder boxes to introduce fish with already aggressive fish in the tank, changing up the aquascape, etc., are all techniques to manipulate our fish in our favor based on knowing natural tendencies of certain species and observed behaviors in the wild.

Probably the best studies on fish behavior are in zebrafish because they are a very commonly used animal model. I'm sure if someone did some literature searching they could find more data on this but extrapolating conclusions from those studies or even studies in the wild to a home aquarium is probably also difficult.

Good discussion though! I don't think many hobbyists think much about the things they cannot see (like pheromones). It seems pretty common for us to talk about coral behaviors/responses to some of their chemical warfare but people don't often think about this when it comes to fish and how they also use chemoreception in response to the world around them.
All great points. However, I don’t think we give other species the intellectual credit they deserve. A fish’s intellect is more based on genetics, instinct and focused strictly on survival. We humans very seldom find ourselves in an absolute survival scenario and our superior intelligence in those situation may not be as good as the fish’s is.

Great discussion. For those who think the fish’s world is more visual based, run this scenario. I don’t have the answer, but I’m partial to the smelly side. The Powder Blue has been voted in many poles as the most aggressive. Usually a loner and protects his, or her own little piece of the reef. So, a second Powder blue shows up in its territory. Now the male and female Powder Blues look identical. How does the owner of that piece of turf determine whether the intruder is an absolute threat, or maybe a possible mating partner? Territory, food supply and mating hold pretty much equal value. Does it attack, or investigate. I say sight won’t help it, but smell (through pheromones) will. Smell will not only tell if the intruder is male or female, but also whether the intruder has hostile intentions or is also looking for a mate. The sense of smell is vital for survival fish and most other species. We humans go the opposite direction and use deodorants, perfume and whatever measures we can to cover up our scents so no one can smell them. Just saying.

Jetson
 
Orphek OR3 reef aquarium LED bar

Lasse

7500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 20, 2016
Messages
9,846
Reaction score
27,858
Review score
+0 /0 /-0
Location
Källarliden 14 D Bohus, Sweden
Okay, I’m not a scientist, marine biologist or someone who has been doing aquariums for 50 years. But, I do sometimes question what I read. When something doesn’t make sense, I go looking for the WHY it doesn’t. This is one of those times. Hope this doesn’t offend anyone, and makes a few laugh in the process. Here goes:

Can’t count the number of times I have read threads here, and elsewhere, where it is said that if a Tang sees another that looks like it, then it will be aggressive toward that fish. Hum?? Let me think about this. The question that comes to mind would be; how does a Tang, or any other fish for that matter, that lives in the ocean, or aquarium, actually know what they look like themselves? Well…..maybe there are little reef area restrooms where they can go in and look at themselves in the mirror. No, probably not. Don’t think they would remember what their parents looked like. Guess their best friend could describe how they look to others. No no, that can’t be it. They can see their reflection in another fishes eye. No, no? I think the answer is, fish have no idea what they look like themselves. So, saying if it sees another that looks like it, it will be aggressive toward that fish just doesn’t seem to wash.

So, where did this wive’s tale get started? Well, that could take years to figure out. It will be easier to determine why it got started. I believe it got started, because that’s what “we” see. Not what the fish sees.

Yes it’s true, if a tang sees another new fish that “looks” exactly the same, or similar, in most cases it will be aggressive toward that fish. But why. Fish don’t know what they look like themselves, so what is it? The simple answer is smell. We humans are one of the few species on this planet that use sight as our primary sense. Most other species use smell. We use it to some extent. If we smell a skunk, we know one is close and become more vigilant. But we usually rely on sight. Most species use smell to identify themselves and to use smells of others to identify them as friends or foes. Our little fish friends do it well, and have to because the water may not always be pristine clean. All species, including us, release scents known as pheromones. A simple definition is “A pheromone is a chemical that an animal produces which changes the behavior of another animal of the same species”. Fish, along with all other species, use this and other means such as urine, feces and body sweat to identify themselves, others, mark territories, warn off competitors or attract mates.

Fish (especially tangs) are aggressive for three reasons. Territory, food and mating (basic essentials of survival). There are a few that are genetically predisposed to display hyper aggression, but that’s another topic. So the answer is, “when a Tang sees another that looks exactly like it, it will be aggressive toward that fish” should be changed to “when a Tang senses another Tang, usually of the same species (through identification of pheromones), it will become more aggressive toward that fish because it activates the Tang’s basic survival instincts. Interesting note, pheromones are also used to identify siblings. Those fish which are siblings would probably not be aggressive toward each other. Tangs, and other fish can also be aggressive toward unrelated species. That goes back to the basic instincts of territory, food and mating rights. Or, I guess you could say the easy answer is, they just don’t like the way they smell.

Now, I know someone is going to say, well when you put a mirror in front of it, it becomes aggressive and can’t smell the mirror image. Ah, true. But ask yourself why that happens. Imagine. Tang approaches mirror to examine the new fish. Mirror image swims toward Tang. Tang stares at mirror image. Mirror image stares back. Tang makes a jester of dominance by flaring fins. Mirror image does the same. Well, in my world as a fighter pilot, it would be time to say “fights on, fights on” because no one is backing off. Tang and it’s reflection both attack. Now, as time goes by, the Tang stops flaring at the image and the image stops flaring back. No more aggression. Time to remove the mirror. The Tang is not attacking its reflection, it’s attacking another fish that displayed similar aggressive moves. Pretty much identical moves.

So, okay, I’ve stopped running around in tight little circles. Remember, this little episode was only about fish knowing what they look like. All the other instinctual aggression reasons are still in play. Since we all (most all) love our Tangs, I hope this will help a little in understanding their predisposition. They can’t help themselves because basic genetic survival instincts are hard wired in them and they have a hard time over coming it. Guess It would be like a Tiger letting another unrelated Tiger share its domain. Probable won’t happen without a lot of pain, caring and understanding. But, we will keep trying, because that’s who we are.

Jetson

Interesting perspective but "smell" or chemoreception is not the simple answer here. I would argue visual cues are a major factor in interspecies and intraspecies aggression seen in home aquariums, at least in the short-term when decision for fight or flight is necessary. If this was not the case, then experts in the hobby would not recommend adding new tankmates to a tank when the lights are off. If it was mainly dependent on chemoreception, then poor visibility (via turning the lights off) would have no effect on mitigating aggression. Typically diurnal fish with good eyesight rely on their sense of sight first and other senses secondarily but this is dependent on species and the behavior relying on the sense. In the case of a tang who immediately displays aggression, it is from the sight of the fish and not the "smell". In the case where a tang who normally has no issues with other tankmates suddenly displays aggression toward another fish in the tank, then I would say it was more likely triggered by some other sense assuming nothing else has changed in the tank from the aquarists perspective. This could be for a multitude of reasons like you mentioned sexual maturity or even sometimes fish can sense disease in other fish and will attack them for that reason.



I think you might be giving too much credit to the intellect of a fish. When we say that they are aggressive toward fish that "look" similar, we don't assume the fish has a sense of self in the way that we have a sense of self. Fish use visual cues based on evolved instincts to know how to react to something they see. For instance, they may use smell to find food but they use their sight to decide whether they can actually eat that food. This decision is based on many factors but a few visual ones would be like size, shape, movement patterns, and color (to an extent, because colors are distorted underwater). While a yellow tang may not know that it is a 3 inch, laterally compressed, yellow fish, they do understand relativity. There are so many factors that go into whether a fish attacks something but I don't think it is as simple as just "smell". Ask my royal gramma who attacks my algae scraper every time I'm cleaning the glass. He doesn't attack it when it is just still in the tank, even when it is in his claimed "territory" but the moment I start making slow jerking movements with it he suddenly goes after it striking multiple times around the tank. In this case the gramma is responding to movement, shape, and size of the object and not simply "smell".

The whole topic is very complex and nuanced but basic principles known from evolutionary biology and the study of animal behavior can help guide us to make the best possible decisions for our pets. Introducing fish in order of less aggressive species to more aggressive, introducing fish with the lights off, using breeder boxes to introduce fish with already aggressive fish in the tank, changing up the aquascape, etc., are all techniques to manipulate our fish in our favor based on knowing natural tendencies of certain species and observed behaviors in the wild.

Probably the best studies on fish behavior are in zebrafish because they are a very commonly used animal model. I'm sure if someone did some literature searching they could find more data on this but extrapolating conclusions from those studies or even studies in the wild to a home aquarium is probably also difficult.

Good discussion though! I don't think many hobbyists think much about the things they cannot see (like pheromones). It seems pretty common for us to talk about coral behaviors/responses to some of their chemical warfare but people don't often think about this when it comes to fish and how they also use chemoreception in response to the world around them.

Let’s assume this happens at night where the Tiger can’t see either. Fairly certain that through smell, that Tiger knows whether it’s food, competition or a mating opportunity. Even in daylight, that tiger may not be able to visually distinguish between a male and female Tiger, but if he can smell it, he will know whether it’s danger or a mating opportunity.



I think for us humans it’s called Prince Valium.



All great points. However, I don’t think we give other species the intellectual credit they deserve. A fish’s intellect is more based on genetics, instinct and focused strictly on survival. We humans very seldom find ourselves in an absolute survival scenario and our superior intelligence in those situation may not be as good as the fish’s is.

Great discussion. For those who think the fish’s world is more visual based, run this scenario. I don’t have the answer, but I’m partial to the smelly side. The Powder Blue has been voted in many poles as the most aggressive. Usually a loner and protects his, or her own little piece of the reef. So, a second Powder blue shows up in its territory. Now the male and female Powder Blues look identical. How does the owner of that piece of turf determine whether the intruder is an absolute threat, or maybe a possible mating partner? Territory, food supply and mating hold pretty much equal value. Does it attack, or investigate. I say sight won’t help it, but smell (through pheromones) will. Smell will not only tell if the intruder is male or female, but also whether the intruder has hostile intentions or is also looking for a mate. The sense of smell is vital for survival fish and most other species. We humans go the opposite direction and use deodorants, perfume and whatever measures we can to cover up our scents so no one can smell them. Just saying.

Jetson
Now we are talking :)

My general idea to use my refugium as adaption part of my aquarium for a week or two in order to limit bullying during introduction of new fish comes from experiences with one of the most aggressive groups of fishes - the cichlids of the great lakes of Africa - especially the Tropheus group of Lake Tanganyika. They live in loosely groups around the rocks and often with individual patterns on the body and different geographical "races" differ a lot in colouration. In aquarium have it been shown that large groups - 15 - 30 individuals introduced at the same time works well but any try to let another conspecific (and of the same local population) enter the group end in death. We did some trials back in the 80:ties there we let fishes of the same population swim in different aquariums but insight of each others. The problem was that they are mouthbrooders and we took out the females (after spawn) to separate brooding aquariums and it took around 1.5 months before we could put them back (25 day of brood + recovering time) and many times they was seen as newcomers and get hunted to death. However - to let the females be insight for the old population (but not in the same water) did not help up the situation. One of us come up with the brilliant idea to change water in the brooding aquariums with help of water from the DT on a daily basis and suddenly it works to put the female back. Of Course we moved some of the aquarium out of sight but keep the daily WC with DT water and suddenly that work too. The only answer here is smell. We did this with newcomers too and it works rather well - there was some aggression but did seldom end with death.

After starting to use this method when I introduce new fish to my reef aquarium - the allospecific bullying has disappeared and the conspecific has gone down to an minium - only chasing when they are in sight but not turning every stone upside down. So yes - I believe that with my fishes and in my aquarium - smell play a role. I do not have Tangs but lately I introduce first 8 damsel fishes from the genera Chrysiptera ( 3 C. parasema and 5 C. springeri) and 14 days later another 2 of each species (aquarium 80 gallons) and it works out good. The first 3 C. parasema was hunting the new ones as fast they see them but out of sight - they did not bother. Next day they can spot each other but not any chasing if they not are to close - normal Chrysiptera behavior:)

I´ll think that there is differences between different species how the conspecific identification works. Even if I - as @AKL1950 - have difficult to see how a fish can recognize a conspecific individual only by it looks like - there to many examples of territorial species that have different colouration between males on one hand and females/offsprings on the other even outside reproduction periods. Also fishes with distinct feeding behavior between youngsters and grownups can have colour diphormish because they does not compete for the same food. Many fishes have also different colouration and pattern during breeding - in some way - many fish must recognize individuals from the same species by appearance in shape or color / combination of both .

With tangs - I think its is difference between aquarium and real life. The powder blue mentioned earlier can in the wild swim in large numbers resembling shoals but fight in an aquarium. On the other hand - Yellow tangs and the Red Sea Sailfin can exist more than one in the same home aquarium.

Sincerely Lasse
 

Duncan62

Valuable Member
Review score
+0 /0 /-0
View Badges
Joined
Oct 4, 2021
Messages
1,458
Reaction score
1,281
Review score
+0 /0 /-0
Location
Kannapolis
@Lasse has a very interesting method of introducing fish to his display. I believe he puts them in the sumps so the fish have time to "smell" the soon to be added fish. Apparently, this works well for him, and reducing aggression.
I started this after reading it. It really helps with aggression. Great idea from Lasse!
 
BRS

Does it matter to you whether your fish are captive-bred or wild caught?

  • I only buy captive bred fish.

    Votes: 33 12.5%
  • It matters, but I will buy either captive-bred or wild-caught.

    Votes: 205 77.4%
  • I think wild-caught fish are the better option.

    Votes: 3 1.1%
  • I don’t care where the fish were bred.

    Votes: 24 9.1%
Top