We hear the expression “Clean Up Crew” used a lot in the hobby. What exactly does that mean, anyways?
Seems like every vendor offers an assortment of animals that we designate as “cleaners”- animals that are tasked with consuming uneaten food, detritus, and algae. Usually, the “crew” consists of animals like various snails, crabs, starfish, urchins, etc.
The irony is that we have given these animals “duties”, when, in reality, they are simply behaving as they have in the wild for eons. We’re assigning a “role” to their existence based on our needs…Weird, huh? Or kind of arrogantly presumptive, maybe?
There are a lot of animals from which to choose. Many are of debatable value in terms of consuming things that we don’t want in our tanks. Others are without debate perfectly suited for what we want them to do. Some arise from live rock in a decidedly natural manner, without our intervention. The composition of these “cleanup crews” is a well-discussed topic…We’ve dutifully assembled rosters of animals that we feel will do the job at removing the stuff we don’t want in our reefs.
Everyone has their opinions of what animals are best, and how many you should have. “X” number of this-or-that per gallon, or some such nonsense. I think it’s absurd. I mean, really, who has done studies on how much algae an individual Turbo snail will consume in nature? Yet we as vendors and hobbyists come up with exotic formulae…based on…what? And how much algae can support “X” number of snails in a reef aquarium, and for how long? At some point, food supplies will be exhausted with a large population of these animals in residence.
I mean, if I’m a snail, I wouldn’t want to share my 30 gallon tank with 15 other hungry neighbors. I’d just want the space for myself, or maybe a few friends of the opposite sex. More food, more fun…If you can call a snail’s life “fun”, that is.
So, I figured, why not put my little spin on the whole notion of a cleanup crew, and what I think it should be comprised of? At the very least, it will make you think more. At worst, it will tick you and the rest of the hobby and industry off (like THAT is new), as I question long-held truths about the ethics and thought processes involved in utilizing these animals. And some of my thoughts might surprise and/or even confuse you (what else is new?). I’ll even expose my own hypocrisy about selling some of these animals on my website, so my detractors can get their ounce of flesh, too.
So, without further nonsense, let’s get into my idea of a solid “cleanup crew”.
First off, like so many things in reef keeping, aviation, health, or finance- I’m a believer in multiple redundancies. You should have several ways to cover each requirement. So, for example, I’d want animals that cover the “tasks” of consuming uneaten food, micro algae growth, gross particulate matter ( like fish poop and such), and maybe giving the accumulating detritus a once-over. This may require several different types of animals to do the job.
Let’s talk about the apparent dreaded "enemy" of clean reef tanks…detritus!
Detritus (or “detrus”, as one of my local reefer friends annoyingly refers to it with his typical malapropisms) is a great scientific-sounding “catch all” term for “stuff” that accumulates in your rock and sand- mainly, partially decomposed or uneaten food, coral mucous, fish waste, etc. The working definition is “non-living” organic material; or more properly, organic-rich particulate material. Although continuously broken down by microorganisms in a healthy, established aquarium, some of the materials are not completely consumed by these lower organisms, and can be at least initially “worked over” by detritivorous animals and fishes.
Is it bad? Well, yes and no. I mean, if the materials in the detritus continue to break down, they can create less hygienic conditions in a closed system, or provide “fuel” for nuisance algae growth. However, if you embrace it and view it as a supplemental food source for your animals, which it is- it doesn’t seem all that bad, huh? Chew on this: (I couldn’t resist, sorry) According to Shimek, the typical copepod fecal pellet released near the surface is eaten and re-eaten about 8 times before it hits the bottom of the ocean…Talk about nothing going to waste!
So who eats this stuff?
Well, you might be surprised!
Tons of different animals make detritus a significant part of their diet. Many you will never really see (or at least, not easily), such as “Spaghetti Worms”, bristle worms, nematodes, foraminiferans, amphipods and copepods. There are even microscopic detritivores. This is popular stuff! And of course, there are various starfishes, etc. that consume this stuff as well.
My favorite consumers of detritus? How about Ctenochaetus Tangs, such as the Kole Tang or Chevron Tang? Yeah, they have specially adapted mouthparts that are just perfect for combing detritus. They have the added benefit of being really good at rasping diatoms from rock and hard surfaces…sweet! But wait, there’s more! Even sexier detritivorous fishes are available from the genus Centropyge…Yeah, your Flame Angel, Coral Beauty, etc. is really good at eating this stuff…and again, will pick at algae, too! Well, sure, they might be implicated in pecking at corals, but they are really not all that interested in the coral tissue. They’re more interested in the mucous and algae and uneaten food that might be hanging out in the coral branches or tissues. Even though they eat lots of prepared foods readily, they’re ecologically adapted to hunting and pecking for detritus and algal films throughout the day. So really, one could make a highly persuasive argument that these fishes can be an integral part of your “cleanup crew.” They earn their keep, for sure!
"No, honestly- I luuuurve detritus!"
One of the big problems I have with some of the more “traditional” detritivorous “cleanup crew” members is that they are often animals that consume detritus as a part of their diet, and make a greater part of their diet the micro and/or macrofauna that you are so carefully trying to cultivate for your biodiveristy and nutrient export processes. To make matters worse, hobbyists are often advised to keep large numbers of these animals in their reefs, which assures that not only will they decimate your beneficial infauna, but they’ll probably slowly starve to death as a result of their own efficiency. I mean, Brittle stars and some of the snails we use are good at getting at detritus, but if part of what they are consuming are animals that you want in your system, particularly in your sandbed- then its a considerable tradeoff, isn’t it?
One snail that I love for consuming detritus is the Cerith snail. Its Latin Name is Cerithithium sp. It reaches maybe 2-3 inches in length ,and is one of the more useful and less “damaging” snails that you can incorporate into your reef system “cleanup crew.” Cerith snails do double duty, consuming algal films as well! They reside in the benthic areas of your reef system, searching for diatoms, algae and sediment, cleaning the substrate as well as aerating it as they move. Awesomely, they will also consume algae that forms on inside tank walls. They are also pretty darned good at removing soft algae films from all sorts of surfaces.
Ceriths do it better...
These snails are easy to keep happy, as long as you have a mature system and an ample growth of algae and diatoms to feed upon. They even “right” themselves when they topple over- which is a good thing in a tank full of hungry potential predators! Okay, so Scott likes these snails…but how many should you keep? Answer: I don’t know? I would start with a few- maybe like half a dozen in your 100 gallon reef. I mean, if they’re not doing an adequate job keeping sand, glass, and other surfaces clean, you can always add to the population, right? Better to have them just keep up with algae growth and detritus than having 50 of them in your reef, slowly starving to death. Just my two cents worth.
Another great snail is the Nassarius. These cool snails reach a length of around 1.5” or so, and are superb sanded animals. they spend pretty much full time “submerged” in the sand bed with their snorkel-like proboscis sticking out, and emerge like zombies when you put food in the tank..It’s really amazing to watch, and kids love ‘em!
Now we can segue way into algae-eating snails and other animals…
So-called “Turbo” Snails are yet another one of the creatures that we commonly keep as part of a “cleanup crew”, more so as algae consumers, although they are of dubious value, depending upon where they are collected from. Most of the ones found in the trade are found in Baja California, which is sub tropical, and they may only live a fraction of their lives in tropical reef tanks. Many of us in the trade have sources for these snails which are supposedly in tropical Mexico, but in the end, we just don’t know for sure where the vast majority come from. Living a few months in a reef tank is not acceptable for an animal with a documented longer life span in nature. This is another popular animal which I will personally rethink about carrying in the future.
"No, really. I'm from tropical Mexico. Really."
Honestly, a number of the snails that we incorporate into our cleanup crews are not even tropical species, such as the so-called “Margarita Snails”, and they tend to not survive for extended periods of time, hence the “expendable” mindset that we have about them. I mean, not only do we overstock the heck out of them in our reefs- we keep them in temperatures that are not consistent with their long-term survival. Not good. Oh, there are tropical species of Margarites, but they are found like 1,000 feet down or more. The ones we see in the trade from this genus are subtropical species.
Trochus are pretty cool, are found in tropical waters, eat large amounts of algae, and even reproduce readily in reef systems. A much better long-term sustainable choice for reef systems. They are surprisingly agile animals, and are a pleasure to watch as they work away on algae films. Again, my recommendation is to stock your reef very lightly with these animals, and they’ll let you know if they are happy and healthy by reproducing.
Starfishes are interesting, but the sad reality is that we really haven’t been all that successful at keeping them for long periods of time. It’s kind of hypocritical then, that my company even offers them. Nonetheless, they do fill a useful role in the aquarium, and many species can survive for extended periods of time if their needs are understood and met.
Fromia- they are small and cool-looking, but they, well- suck- as aquarium animals to date. Most don’t hang on much more than a year as they slowly starve to death.
Linckia- Although they appear to be harmless to most reef aquarium inhabitants, we don’t really know all that much about what they eat, either. It’s thought by marine scientists that they are predators on small sessile animals, but no one is 100% certain. For some reason, in hobby literature, we call them consumers of “bacterial and algal films.” Okay, I suppose..but no one really has the science to confirm that.
I mean, just because the animal roams across the sand and has some stuff stuck to it doesn’t mean it’s “consuming” anything. The sad reality is that these probably slowly die in our tanks from inadequate nutrition. My reoccurring theme arises yet again: Just how many small sessile creatures does the average reef tank support? Enough to meet the nutritional needs of one starfish, or even several, as hobbyists are “recommended” to stock as part of their “cleanup crews?”
Assorted “sand-sifting” Starfish- Although many of these creatures are known to consume some small benthic organisms, they are not specifically known to science to be “detritivores”, and it begs the question again- just how much food does the average reef system produce for one or more of these animals? Since we don’t really have a definitive handle on just what they eat, I don’t really think that we are equipped to answer that question, do you?
We do have a better handle on the Ophiarachna brittle stars. These guys are commonly kept in reef tanks as “scavengers”, a role which some do adapt to…However, the vast majority are actually opportunistic predators, and continue this behavior in the aquarium, going after your shrimp, gobies, blennies, and other small, relatively inactive fishes. And I’ve seen them do this many times…If you don’t think a starfish can move quickly, you’ll change this opinion when you see one go after a bottom-dwelling fish!
There is one species of brittle star that is a true detritivorous scavenger, who’s dietary needs are somewhat better understood by science, and that’s the so-called “Mini Brittle Star”, Amphipholis sp. You can get these from fellow hobbyists, stores, or my favorite on line source, Indo Pacific Sea Farms (: : : : Indo-Pacific Sea Farms : : : :). They are really small (like around 1-2 cm in diameter, and reproduce apparently at will in reef systems. They actually DO consume detritus and small-sized food particles. You’ll see them in the sand, and in macro algae clumps, such as Chaetomorpha.
"Okay, so I'm like the only Brittle Star that Fellman likes. What does THAT get me, huh?"
Sea Cucumbers also have a sort of well-known reputation for seemingly “thriving” for a while, then fading away into oblivion following a prolonged starvation process. We just don’t have a great handle on what these guys need long-term to survive. It’s known that they consume microfauna that reside in sand beds. And, as discussed previously, it’s hard to estimate just how many small creatures suitable for eating live in a typical reef aquarium sanded…And then there’s the same question: Why would you want to keep an animal that consumes other beneficial creatures?
Yikes, I’m a total buzkill, especially for vendors who sell all of these animals as “cleanup crews.” However, I’m giving you my opinion, based on my experience and personal research. Not passing judgement. We, as hobbyists, tend to view these animals as “expendable”, and simply “restock” them periodically after they fade away (ie; starve?), as if they are paper towels or a bar of soap. Again, not passing judgement, but I am asking us all to take a good honest look at what we are doing. Perhaps this will lead to better, or more realistic, stocking scenarios for many of these animals.
Guess what? As a hobby and industry, we all need to rethink our use of these animals. That includes my company, so I shouldn’t be a hypocrite. We do sell some of these animals, and probably should limit the ones that we do sell. It’s something that I’m going to revisit again, and I encourage other vendors to do the same.
Sea Urchins are another valuable member of the so-called “cleanup crew”, but, like the snails, starfishes, and other animals so employed, there are caveats to their inclusion in such a scenario. In my opinion (Oh, here goes “Captain Buzkill” again), the only ones that we should really be playing with would be the Tuxedo Urchins, Mespilia globulus. They are known to consume coralline and filamentous algae in the wild and in reef aquariums, and are not really interested in much ease. They are really good at grazing! Sure, they might accidentally chew up some encrusting corals or small inverts in search of their favored foods, but this is largely unintentional, and you need to accept the possibility of some slight “collateral damage” to desirable aniamls, much as you would with Angelfishes in a reef. Like other urchins, they can be a bit “clumsy”, unintentionally knocking over loosely secured corals and sessile inverts on their voyages throughout your reef, looking for algae growth.
And, further adding to my buzz killing- they need a LOT of food. Especially coralline algae. So, my personal practice with Tuxedo Urchins is to keep one to a tank. Much like the starfishes and snails, you have to ask yourself why you’d want to include 10 of them when your system can only realistically sustain one specimen for any appreciable length of time.
Which, of course, brings us to the Hermit Crabs, mostly the genus Calcinus. Yes, they are quite adept at finding and consuming bits of uneaten food, algae, and dead animals. Serious omnivores. The blue-banded and red-banded ones are great looking, too. They move in and out of empty shells as they grow, which means you should toss a few assorted shells in your reef to provide future homes for your little buddies. Yes, they occasionally are “bad actors”, and may take down a snail or two if food sources are limited, so be sure to toss some extra food into the reef just for them now and again, an act of inter-species kindness that is not misspent.
I didn't really get into shrimp, did I? That's because I generally keep them "for the fun of it", and don't expect much out of them except bad attitudes and the occasional dramatic appearance in my systems. They are truly more of a "pet", IMHO, than just about any of the other creatures we've discussed here.
So, you have a very basic, crude introduction to my take on the “cleanup crew” that we all seem to feel that we need. While it’s a valid aim to incorporate such animals into your reef ecosystem, you really need to study the animals that you are thinking of incorporating into your “crew”, and you need to ask yourself just why you are including them. Is it because this is the way it’s always been done, or is it because you have a specific need and understand that the animal might help fill that need?
And further, you should consider each and every addition to your “team” with the same thought and analysis that goes into any animal purchase for your reef. Consider both the needs of the animal, and your system’s ability to provide the animal what it needs for long-term survival. It may be “just a snail” to you, but it’s a living creature that deserves the same respect as any other aquarium inhabitant.
Finally, start small, adding just a few of these animals into your system at a time. Just because “experts” or vendors recommend “X” number per gallon doesn’t mean that’s an appropriate stocking level. Remember, these animals need to eat, and if they exhaust their food supply, they will perish. If the thought of introducing new algae-covered rocks into your reef just to feed your large population of Trochus snails doesn’t appeal to you, then stock with just a few to start and see how they do.
You can always just do it yourself, right?
Obviously, this is a topic that deserves far, far more consideration and discussion than I have been able to include here, but I hope that I have given you some “food for thought”, and that you’ll add your experiences, opinions, and ideas to this thread for further discourse.
Until next time- keep those snails fed, change your water, give frags to a newbie…and stay wet. And special thanks to Zoomer for the topic suggestion...greatly appreciated, especially when coming off of a creative drought! Keep 'em coming!
Scott Fellman
Unique Corals
Seems like every vendor offers an assortment of animals that we designate as “cleaners”- animals that are tasked with consuming uneaten food, detritus, and algae. Usually, the “crew” consists of animals like various snails, crabs, starfish, urchins, etc.
The irony is that we have given these animals “duties”, when, in reality, they are simply behaving as they have in the wild for eons. We’re assigning a “role” to their existence based on our needs…Weird, huh? Or kind of arrogantly presumptive, maybe?
There are a lot of animals from which to choose. Many are of debatable value in terms of consuming things that we don’t want in our tanks. Others are without debate perfectly suited for what we want them to do. Some arise from live rock in a decidedly natural manner, without our intervention. The composition of these “cleanup crews” is a well-discussed topic…We’ve dutifully assembled rosters of animals that we feel will do the job at removing the stuff we don’t want in our reefs.
Everyone has their opinions of what animals are best, and how many you should have. “X” number of this-or-that per gallon, or some such nonsense. I think it’s absurd. I mean, really, who has done studies on how much algae an individual Turbo snail will consume in nature? Yet we as vendors and hobbyists come up with exotic formulae…based on…what? And how much algae can support “X” number of snails in a reef aquarium, and for how long? At some point, food supplies will be exhausted with a large population of these animals in residence.
I mean, if I’m a snail, I wouldn’t want to share my 30 gallon tank with 15 other hungry neighbors. I’d just want the space for myself, or maybe a few friends of the opposite sex. More food, more fun…If you can call a snail’s life “fun”, that is.
So, I figured, why not put my little spin on the whole notion of a cleanup crew, and what I think it should be comprised of? At the very least, it will make you think more. At worst, it will tick you and the rest of the hobby and industry off (like THAT is new), as I question long-held truths about the ethics and thought processes involved in utilizing these animals. And some of my thoughts might surprise and/or even confuse you (what else is new?). I’ll even expose my own hypocrisy about selling some of these animals on my website, so my detractors can get their ounce of flesh, too.
So, without further nonsense, let’s get into my idea of a solid “cleanup crew”.
First off, like so many things in reef keeping, aviation, health, or finance- I’m a believer in multiple redundancies. You should have several ways to cover each requirement. So, for example, I’d want animals that cover the “tasks” of consuming uneaten food, micro algae growth, gross particulate matter ( like fish poop and such), and maybe giving the accumulating detritus a once-over. This may require several different types of animals to do the job.
Let’s talk about the apparent dreaded "enemy" of clean reef tanks…detritus!
Detritus (or “detrus”, as one of my local reefer friends annoyingly refers to it with his typical malapropisms) is a great scientific-sounding “catch all” term for “stuff” that accumulates in your rock and sand- mainly, partially decomposed or uneaten food, coral mucous, fish waste, etc. The working definition is “non-living” organic material; or more properly, organic-rich particulate material. Although continuously broken down by microorganisms in a healthy, established aquarium, some of the materials are not completely consumed by these lower organisms, and can be at least initially “worked over” by detritivorous animals and fishes.
Is it bad? Well, yes and no. I mean, if the materials in the detritus continue to break down, they can create less hygienic conditions in a closed system, or provide “fuel” for nuisance algae growth. However, if you embrace it and view it as a supplemental food source for your animals, which it is- it doesn’t seem all that bad, huh? Chew on this: (I couldn’t resist, sorry) According to Shimek, the typical copepod fecal pellet released near the surface is eaten and re-eaten about 8 times before it hits the bottom of the ocean…Talk about nothing going to waste!
So who eats this stuff?
Well, you might be surprised!
Tons of different animals make detritus a significant part of their diet. Many you will never really see (or at least, not easily), such as “Spaghetti Worms”, bristle worms, nematodes, foraminiferans, amphipods and copepods. There are even microscopic detritivores. This is popular stuff! And of course, there are various starfishes, etc. that consume this stuff as well.
My favorite consumers of detritus? How about Ctenochaetus Tangs, such as the Kole Tang or Chevron Tang? Yeah, they have specially adapted mouthparts that are just perfect for combing detritus. They have the added benefit of being really good at rasping diatoms from rock and hard surfaces…sweet! But wait, there’s more! Even sexier detritivorous fishes are available from the genus Centropyge…Yeah, your Flame Angel, Coral Beauty, etc. is really good at eating this stuff…and again, will pick at algae, too! Well, sure, they might be implicated in pecking at corals, but they are really not all that interested in the coral tissue. They’re more interested in the mucous and algae and uneaten food that might be hanging out in the coral branches or tissues. Even though they eat lots of prepared foods readily, they’re ecologically adapted to hunting and pecking for detritus and algal films throughout the day. So really, one could make a highly persuasive argument that these fishes can be an integral part of your “cleanup crew.” They earn their keep, for sure!
"No, honestly- I luuuurve detritus!"
One of the big problems I have with some of the more “traditional” detritivorous “cleanup crew” members is that they are often animals that consume detritus as a part of their diet, and make a greater part of their diet the micro and/or macrofauna that you are so carefully trying to cultivate for your biodiveristy and nutrient export processes. To make matters worse, hobbyists are often advised to keep large numbers of these animals in their reefs, which assures that not only will they decimate your beneficial infauna, but they’ll probably slowly starve to death as a result of their own efficiency. I mean, Brittle stars and some of the snails we use are good at getting at detritus, but if part of what they are consuming are animals that you want in your system, particularly in your sandbed- then its a considerable tradeoff, isn’t it?
One snail that I love for consuming detritus is the Cerith snail. Its Latin Name is Cerithithium sp. It reaches maybe 2-3 inches in length ,and is one of the more useful and less “damaging” snails that you can incorporate into your reef system “cleanup crew.” Cerith snails do double duty, consuming algal films as well! They reside in the benthic areas of your reef system, searching for diatoms, algae and sediment, cleaning the substrate as well as aerating it as they move. Awesomely, they will also consume algae that forms on inside tank walls. They are also pretty darned good at removing soft algae films from all sorts of surfaces.
Ceriths do it better...
These snails are easy to keep happy, as long as you have a mature system and an ample growth of algae and diatoms to feed upon. They even “right” themselves when they topple over- which is a good thing in a tank full of hungry potential predators! Okay, so Scott likes these snails…but how many should you keep? Answer: I don’t know? I would start with a few- maybe like half a dozen in your 100 gallon reef. I mean, if they’re not doing an adequate job keeping sand, glass, and other surfaces clean, you can always add to the population, right? Better to have them just keep up with algae growth and detritus than having 50 of them in your reef, slowly starving to death. Just my two cents worth.
Another great snail is the Nassarius. These cool snails reach a length of around 1.5” or so, and are superb sanded animals. they spend pretty much full time “submerged” in the sand bed with their snorkel-like proboscis sticking out, and emerge like zombies when you put food in the tank..It’s really amazing to watch, and kids love ‘em!
Now we can segue way into algae-eating snails and other animals…
So-called “Turbo” Snails are yet another one of the creatures that we commonly keep as part of a “cleanup crew”, more so as algae consumers, although they are of dubious value, depending upon where they are collected from. Most of the ones found in the trade are found in Baja California, which is sub tropical, and they may only live a fraction of their lives in tropical reef tanks. Many of us in the trade have sources for these snails which are supposedly in tropical Mexico, but in the end, we just don’t know for sure where the vast majority come from. Living a few months in a reef tank is not acceptable for an animal with a documented longer life span in nature. This is another popular animal which I will personally rethink about carrying in the future.
"No, really. I'm from tropical Mexico. Really."
Honestly, a number of the snails that we incorporate into our cleanup crews are not even tropical species, such as the so-called “Margarita Snails”, and they tend to not survive for extended periods of time, hence the “expendable” mindset that we have about them. I mean, not only do we overstock the heck out of them in our reefs- we keep them in temperatures that are not consistent with their long-term survival. Not good. Oh, there are tropical species of Margarites, but they are found like 1,000 feet down or more. The ones we see in the trade from this genus are subtropical species.
Trochus are pretty cool, are found in tropical waters, eat large amounts of algae, and even reproduce readily in reef systems. A much better long-term sustainable choice for reef systems. They are surprisingly agile animals, and are a pleasure to watch as they work away on algae films. Again, my recommendation is to stock your reef very lightly with these animals, and they’ll let you know if they are happy and healthy by reproducing.
Starfishes are interesting, but the sad reality is that we really haven’t been all that successful at keeping them for long periods of time. It’s kind of hypocritical then, that my company even offers them. Nonetheless, they do fill a useful role in the aquarium, and many species can survive for extended periods of time if their needs are understood and met.
Fromia- they are small and cool-looking, but they, well- suck- as aquarium animals to date. Most don’t hang on much more than a year as they slowly starve to death.
Linckia- Although they appear to be harmless to most reef aquarium inhabitants, we don’t really know all that much about what they eat, either. It’s thought by marine scientists that they are predators on small sessile animals, but no one is 100% certain. For some reason, in hobby literature, we call them consumers of “bacterial and algal films.” Okay, I suppose..but no one really has the science to confirm that.
I mean, just because the animal roams across the sand and has some stuff stuck to it doesn’t mean it’s “consuming” anything. The sad reality is that these probably slowly die in our tanks from inadequate nutrition. My reoccurring theme arises yet again: Just how many small sessile creatures does the average reef tank support? Enough to meet the nutritional needs of one starfish, or even several, as hobbyists are “recommended” to stock as part of their “cleanup crews?”
Assorted “sand-sifting” Starfish- Although many of these creatures are known to consume some small benthic organisms, they are not specifically known to science to be “detritivores”, and it begs the question again- just how much food does the average reef system produce for one or more of these animals? Since we don’t really have a definitive handle on just what they eat, I don’t really think that we are equipped to answer that question, do you?
We do have a better handle on the Ophiarachna brittle stars. These guys are commonly kept in reef tanks as “scavengers”, a role which some do adapt to…However, the vast majority are actually opportunistic predators, and continue this behavior in the aquarium, going after your shrimp, gobies, blennies, and other small, relatively inactive fishes. And I’ve seen them do this many times…If you don’t think a starfish can move quickly, you’ll change this opinion when you see one go after a bottom-dwelling fish!
There is one species of brittle star that is a true detritivorous scavenger, who’s dietary needs are somewhat better understood by science, and that’s the so-called “Mini Brittle Star”, Amphipholis sp. You can get these from fellow hobbyists, stores, or my favorite on line source, Indo Pacific Sea Farms (: : : : Indo-Pacific Sea Farms : : : :). They are really small (like around 1-2 cm in diameter, and reproduce apparently at will in reef systems. They actually DO consume detritus and small-sized food particles. You’ll see them in the sand, and in macro algae clumps, such as Chaetomorpha.
"Okay, so I'm like the only Brittle Star that Fellman likes. What does THAT get me, huh?"
Sea Cucumbers also have a sort of well-known reputation for seemingly “thriving” for a while, then fading away into oblivion following a prolonged starvation process. We just don’t have a great handle on what these guys need long-term to survive. It’s known that they consume microfauna that reside in sand beds. And, as discussed previously, it’s hard to estimate just how many small creatures suitable for eating live in a typical reef aquarium sanded…And then there’s the same question: Why would you want to keep an animal that consumes other beneficial creatures?
Yikes, I’m a total buzkill, especially for vendors who sell all of these animals as “cleanup crews.” However, I’m giving you my opinion, based on my experience and personal research. Not passing judgement. We, as hobbyists, tend to view these animals as “expendable”, and simply “restock” them periodically after they fade away (ie; starve?), as if they are paper towels or a bar of soap. Again, not passing judgement, but I am asking us all to take a good honest look at what we are doing. Perhaps this will lead to better, or more realistic, stocking scenarios for many of these animals.
Guess what? As a hobby and industry, we all need to rethink our use of these animals. That includes my company, so I shouldn’t be a hypocrite. We do sell some of these animals, and probably should limit the ones that we do sell. It’s something that I’m going to revisit again, and I encourage other vendors to do the same.
Sea Urchins are another valuable member of the so-called “cleanup crew”, but, like the snails, starfishes, and other animals so employed, there are caveats to their inclusion in such a scenario. In my opinion (Oh, here goes “Captain Buzkill” again), the only ones that we should really be playing with would be the Tuxedo Urchins, Mespilia globulus. They are known to consume coralline and filamentous algae in the wild and in reef aquariums, and are not really interested in much ease. They are really good at grazing! Sure, they might accidentally chew up some encrusting corals or small inverts in search of their favored foods, but this is largely unintentional, and you need to accept the possibility of some slight “collateral damage” to desirable aniamls, much as you would with Angelfishes in a reef. Like other urchins, they can be a bit “clumsy”, unintentionally knocking over loosely secured corals and sessile inverts on their voyages throughout your reef, looking for algae growth.
And, further adding to my buzz killing- they need a LOT of food. Especially coralline algae. So, my personal practice with Tuxedo Urchins is to keep one to a tank. Much like the starfishes and snails, you have to ask yourself why you’d want to include 10 of them when your system can only realistically sustain one specimen for any appreciable length of time.
Which, of course, brings us to the Hermit Crabs, mostly the genus Calcinus. Yes, they are quite adept at finding and consuming bits of uneaten food, algae, and dead animals. Serious omnivores. The blue-banded and red-banded ones are great looking, too. They move in and out of empty shells as they grow, which means you should toss a few assorted shells in your reef to provide future homes for your little buddies. Yes, they occasionally are “bad actors”, and may take down a snail or two if food sources are limited, so be sure to toss some extra food into the reef just for them now and again, an act of inter-species kindness that is not misspent.
I didn't really get into shrimp, did I? That's because I generally keep them "for the fun of it", and don't expect much out of them except bad attitudes and the occasional dramatic appearance in my systems. They are truly more of a "pet", IMHO, than just about any of the other creatures we've discussed here.
So, you have a very basic, crude introduction to my take on the “cleanup crew” that we all seem to feel that we need. While it’s a valid aim to incorporate such animals into your reef ecosystem, you really need to study the animals that you are thinking of incorporating into your “crew”, and you need to ask yourself just why you are including them. Is it because this is the way it’s always been done, or is it because you have a specific need and understand that the animal might help fill that need?
And further, you should consider each and every addition to your “team” with the same thought and analysis that goes into any animal purchase for your reef. Consider both the needs of the animal, and your system’s ability to provide the animal what it needs for long-term survival. It may be “just a snail” to you, but it’s a living creature that deserves the same respect as any other aquarium inhabitant.
Finally, start small, adding just a few of these animals into your system at a time. Just because “experts” or vendors recommend “X” number per gallon doesn’t mean that’s an appropriate stocking level. Remember, these animals need to eat, and if they exhaust their food supply, they will perish. If the thought of introducing new algae-covered rocks into your reef just to feed your large population of Trochus snails doesn’t appeal to you, then stock with just a few to start and see how they do.
You can always just do it yourself, right?
Obviously, this is a topic that deserves far, far more consideration and discussion than I have been able to include here, but I hope that I have given you some “food for thought”, and that you’ll add your experiences, opinions, and ideas to this thread for further discourse.
Until next time- keep those snails fed, change your water, give frags to a newbie…and stay wet. And special thanks to Zoomer for the topic suggestion...greatly appreciated, especially when coming off of a creative drought! Keep 'em coming!
Scott Fellman
Unique Corals
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