Does fish growth get stunted in an aquarium?

[MoshJosh]

In my unprofessional opinion. . . yes and no.

I think given idea water parameters and consistent parameters combined with high quality foods fed multiple times a day a fish could likely grow to full size in an aquarium, and I would guess in even a smaller than ideal aquarium. . .

That said keeping good clean water in a small tank with a big fish is not easy.

Most of these assumptions come from when I used to keep discus. I was told a story about Jack Watley (famous discus guy), that he once kept a discus in a massive tank and another in a fish bowl, he changed the fish bowl water daily and never changed the big tank. . . the bowl fish grew faster. . . just a story but. . .

Anyway when we want huge discus we give them the cleanest water and the best food.

 

[Randy Holmes-Farley]

I'm highly skeptical that the length that fish attain a reef tank has anything to do with organic molecules of any sort that they secrete into the water.

I recognize that folks believe this is true of koi and goldfish, and not other fish, but for a variety of reasons, I do not think it likely to pertain to reef tanks.

 

[vpierce3]

In my years of reefing (since the 90s) I have kept tangs that got to 10 yrs old and never grew more than 5”-6”. They were happy and very active.
I have rarely seen old aquarium fish get as big as the fish I’ve seen scuba diving; with a few exceptions of course (like the ones mentioned before). That is just my humble experience.

In nature there are many examples of dwarf animals that have adapted to their environment….good examples of this are the Galápagos Islands and Madagascar.
There is even evidence of dwarf humans in past times who adapted in this way over generations.
Nature has a way of adapting. However this is not a loophole for responsible husbandry.

 

[Randy Holmes-Farley]

In nature there are many examples of dwarf animals that have adapted to their environment….good examples of this are the Galápagos Islands and Madagascar.
There is even evidence of dwarf humans in past times who adapted in this way over generations.
Nature has a way of adapting. However this is not a loophole for responsible husbandry.

But that is evolution over many generations, not impacts on a single organism.

Do zoo animals in cages not grow full size?

 

[vetteguy53081]

just had a person from illinois Offer me a powder blue tang at 5" that came out of 40 breeder. He was told it can stay in that tank for about a year until he upgraded, and it reached this size in under 8 months
I'd say tank size doesnt matter not to mention other fish ive seen outgrow tanks

 

[vpierce3]

But that is evolution over many generations, not impacts on a single organism.

Do zoo animals in cages not grow full size?

That’s true…..but it was only an analogy that nature can adapt.
In my experience, I’ve seen most fish (even old ones) that didn’t grow to the same size as their wild counterparts. YMMV.
In the wild, their are lots of animals that can change to match conditions rapidly, such as dogs, cats and most recently a new breed of hybrid feral-domesticated pigs that are invading Montana from Canada.
Animals can adapt. Some don’t. And like I said, this phenomenon is no loophole for irresponsible husbandry.

 

[ReefHog]

My opinion is that it's mostly food related. Fish in the wild are grazing all day. 4, 5, 6, 7 feedings a day is still not the same. Smaller tanks tend to have smaller fish, less filter capacity and are fed smaller foods. Larger tanks have more filter capacity and are better able to process more food waste. I have two tangs in my 150 mostly sps reef. The fish get three daily feedings of LRS reef frenzy, Hikari Mysis, pellets and nori sheets. In my 220 predator mixed reef I feed two daily feeding of LRS Chunky, Hikari Jumbo Mysis and nori sheets. Both tanks consume the food in the same amount of time. Frozen food is all mostly water, but the larger chunks are way more dense than the smaller pieces therefore over all the fish are getting more food with less feedings. While the tangs in the 150 are fat and healthy, they don't grow anywhere as large or as fast as the fish in the 220. Larger tanks also have more rock space for fish to graze. Most public aquariums are covered with algae much like natural reefs providing all day grazing opportunities.

 

[Jacked Reefer]

Marine Biology Student here.
The answer to this question lies in environmental factors. Many fish have what is called indeterminate growth. Meaning that they will continue growing as long as their food intake, genetics, movement capabilities, and a plethora of other factors allow. Granted this growth is much faster when they are larval and juvenile stages. But they will continue putting on mass (it the resources allow) until they age into disease or death.

now this model of indeterminate growth only occurs if there is an ideal amount of resources. Which I don’t believe occurs in our aquariums for most species. Take tangs for example. In the wild they will have a constant supply of any algae within a few hundred square miles to consume. No limit on the direction of horizontal travel. Constant competition from conspesifics.

in captivity none of these factors for ideal growth are met. Perhaps the tang has 5-6 feedings per day and a solid 12 feet (diagonally in a 10 foot aquarium) of horizontal movement space. It still will not reach the full mature size that it could have at the same age in the wild.

the opposite is true for fish like clownfish and damsels. The space, food, habitat, and competition are almost all provided in an aquarium setting, but the thread of predation is removed. Meaning it is likely the same clownfish gets bigger in captivity than it would in the wild.

i have seen many comments discussing hormones in the water slowing growth. This is true for many freshwater fish that live in ponds, pools, and puddles that their resources are limited by space and conspesifics. So the hormones are release to stop the growth of all fish of that same species in the body of water ensuring higher survival. I have not seen anything that indicated this would be the same for a marine setting.

unfortunately aquariums are not well respected or well researched by most fields of marine biology, including fish physiology. Meaning we probably won’t get a concrete answer any time soon. But we can definitely speculate!

 

[\m/reefsnmetal\m/]

This is good to know. Anyone else experienced this?

Also, did you ever transfer a fish that had stopped growing in a smaller tank to a larger tank and observe it to start growing again ?

I had a weird scenario with sailfin tangs. I put a one in a 75 and a slightly bigger one in a 125. The larger one grew significantly to the point it was too big for the 125 so I sold it to someone with a larger tank. The one I put in the 75 stopped growing, but a year after transferring it to the 125 I haven’t seen any growth.

 

[Randy Holmes-Farley]

That’s true…..but it was only an analogy that nature can adapt.
In my experience, I’ve seen most fish (even old ones) that didn’t grow to the same size as their wild counterparts. YMMV.
In the wild, their are lots of animals that can change to match conditions rapidly, such as dogs, cats and most recently a new breed of hybrid feral-domesticated pigs that are invading Montana from Canada.
Animals can adapt. Some don’t. And like I said, this phenomenon is no loophole for irresponsible husbandry.

Im not saying there isn’t an effect. I don’t know if there is or not. I just do not believe it is from chemicals in the water, if there is one, and we should be careful about analogies that are clearly for different reasons than can possibly be happening in aquaria (evolution and selection of fish traits over generations, for example).

 

[Tired]

In nature there are many examples of dwarf animals that have adapted to their environment….good examples of this are the Galápagos Islands and Madagascar.
There is even evidence of dwarf humans in past times who adapted in this way over generations.
Nature has a way of adapting. However this is not a loophole for responsible husbandry.

That only works over many, many generations. It happens because the animals live in an environment with limited food and other resources, so staying small is a trait that gets selected for. It may also have to do with epigenetics, but that's another multi-generational process, and is again related to food- not to space. A Great Dane kept in a closet will still grow to Great Dane size, it's just gonna be miserable.

 

[WestMI-Reefer]

I pretty sure fish will emit hormones into the environment, some of which directly inhibit growth.

 

[RichReef]

I have had aquariums since I was 6 years old. I am now in my 50s.

I had a large mouth bass for 6 years that never grew more than 4 inches in a 30 gallon. Was a pig. The crappy bass outgrew him.

Even sunfish that never grew as large as the ones in the creeks and ponds. Same 30 gallon.

I had a snakehead that grew bigger than the tank. Couldn't turn around without going up. 55 gallon.

Had piranhas that stayed on the small side in a 20 long. Exploded when put into a 55 4 years later.

Had freshwater angelfish that also stayed small until they went into a bigger tank.

I have a yellow tang for almost 12 years now it's just under 4 inches. Same with a purple. Best buds by the way. Exact same size.

A lionfish for 3 years that outgrew the tank .. fast. 30 gallon. Body was 7 inches long. Probably why some thought it was a good idea to let them go in Florida. Grew too big.

I guess what I am getting at is it all depends on the species.

I don't have scientific research as far as data. But this has been my experience. If you don't know the fish you won't be able to determine how big they can get in a particular aquarium.

 

[Malcontent]

I pretty sure fish will emit hormones into the environment, some of which directly inhibit growth.

Hormones are for internal signaling. All animals have growth regulating hormones otherwise they'll never stop growing and we'd all be like Andre the Giant.

 

[Jacked Reefer]

Hormones are for internal signaling. All animals have growth regulating hormones otherwise they'll never stop growing and we'd all be like Andre the Giant.

Not if you have indeterminate growth like a fish or reptiles. But yeah it does slow down when they are bigger. And only some freshwater fish use external growth regulating hormones as far as we know

 

[Malcontent]

Not if you have indeterminate growth like a fish or reptiles. But yeah it does slow down when they are bigger. And only some freshwater fish use external growth regulating hormones as far as we know

Someone already posted a paper about growth regulating hormones in fish:

Does fish growth get stunted in an aquarium?

I was at my lfs, which is run by very knowledgeable staff. We were discussing which tangs can go into what size aquariums. At one point they mentioned that fish typically do not get as large in an aquarium. For example, if you put a baby yellow tang (think of those captive bred 1” babies that...

www.reef2reef.com

 

[fish farmer]

Marine Biology Student here.
The answer to this question lies in environmental factors. Many fish have what is called indeterminate growth. Meaning that they will continue growing as long as their food intake, genetics, movement capabilities, and a plethora of other factors allow. Granted this growth is much faster when they are larval and juvenile stages. But they will continue putting on mass (it the resources allow) until they age into disease or death.

now this model of indeterminate growth only occurs if there is an ideal amount of resources. Which I don’t believe occurs in our aquariums for most species. Take tangs for example. In the wild they will have a constant supply of any algae within a few hundred square miles to consume. No limit on the direction of horizontal travel. Constant competition from conspesifics.

in captivity none of these factors for ideal growth are met. Perhaps the tang has 5-6 feedings per day and a solid 12 feet (diagonally in a 10 foot aquarium) of horizontal movement space. It still will not reach the full mature size that it could have at the same age in the wild.

the opposite is true for fish like clownfish and damsels. The space, food, habitat, and competition are almost all provided in an aquarium setting, but the thread of predation is removed. Meaning it is likely the same clownfish gets bigger in captivity than it would in the wild.

i have seen many comments discussing hormones in the water slowing growth. This is true for many freshwater fish that live in ponds, pools, and puddles that their resources are limited by space and conspesifics. So the hormones are release to stop the growth of all fish of that same species in the body of water ensuring higher survival. I have not seen anything that indicated this would be the same for a marine setting.

unfortunately aquariums are not well respected or well researched by most fields of marine biology, including fish physiology. Meaning we probably won’t get a concrete answer any time soon. But we can definitely speculate!

Here's a question for you, I noticed you mentioned genetics.

How much does genetics influence the growth of those tangs once they are settled and then scooped up for the aquarium trade?

Do all those 2 inch tangs coming to market have the potential genetically to reach maximum size in a specific amount of time?

Do the runts of the litter eventually get eaten/die off or do they maintain themselves eventually reaching an adult size but at a slower pace?

I always wonder if there is a size variability which comes into play with wild collected fish especially if they are collected at a young age.

 

[Randy Holmes-Farley]

I pretty sure fish will emit hormones into the environment, some of which directly inhibit growth.

Based on what info? Generalizing from fish that live in different environments to marine fish is likely not correct (IMO)

What possible reason would there be for ocean fish to have this attribute?

Also, reefers go to considerable extents to remove organics.

And finally, would a single fish inhibit itself from growing? That seems really odd if true, and if not, one would expect singleton fish to get larger than those in groups.

 

[Jacked Reefer]

Here's a question for you, I noticed you mentioned genetics.

How much does genetics influence the growth of those tangs once they are settled and then scooped up for the aquarium trade?

Do all those 2 inch tangs coming to market have the potential genetically to reach maximum size in a specific amount of time?

Do the runts of the litter eventually get eaten/die off or do they maintain themselves eventually reaching an adult size but at a slower pace?

I always wonder if there is a size variability which comes into play with wild collected fish especially if they are collected at a young age.

As I mentioned before, fish have an indeterminate growth model. Theoretically all the genetics would be able to do is dictate exactly WHEN to activate periods of fast growth VS. slow growth. This is mainly dictated by temperature, food supply, competition, so if any of those things are lacking for an extended period of time. It is highly possible that you do have a permanently stunted fish.

I imagine it also would be possible for the hormones of the fish to to get switched into a permanent “slow” state though genetics from a very small size. But I can’t say I’m aware of any situation where this has been documented happening. Either becasue it doesn’t happen or it happens so much it isn’t noteworthy to dedicate a study too.

but as a short answer to your question. Genetics dictate anything that goes on in an organism. The 100 percent is a mitigation that leads to dwarfism or super slow growth in fish. But whether predators eat them all or they have other problems because of that mutation is a different question.

mad for our tanks. If you were to feed 2 fish of the same species the same thing, keep them in identical scenarios with different parameters and settings. You most likely will end up with 2 different sized fish. Working in this hobby for 4 years I have seen yellow tangs in 90 gallons that clock in at 8.5 inches, but many in a few hundred gallon systems that barley hit 4-5. It’s very hard to believe that is ALL because of food and tank space.

 

[vpierce3]

Im not saying there isn’t an effect. I don’t know if there is or not. I just do not believe it is from chemicals in the water, if there is one, and we should be careful about analogies that are clearly for different reasons than can possibly be happening in aquaria (evolution and selection of fish traits over generations, for example).

With all due respect, OP asked for everyones opinion and experience and that’s what I gave. I understand that you have a different view. And from what I’ve read of you posts, you are very knowledgeable. However I will continue to express myself the best way I can.