Presented by Charles & Linda Raabe
Mactan Island, The Philippines
© 2010 All Rights Reserved

  When first establishing a marine aquarium the first inhabitants added to the system are the members of what is know as the "Clean up Crew". This crew is almost always comprised of a mixture of snails, hermit crabs and starfish as recommended by any number of local stores or those found online.
  This article will address what I feel has become a bad habit within the hobby. The use of species that are not suited for a tropical rocky habitat and in numbers that far exceed the aquarium's ability to provide for their needs. Some of this information, if you care to use it, will require you to be able to identify the various species that are offered for sale. I will include links to online resources that will hopefully allow you to do so.

Your best source for proper clean up crews!
I highly recommend Reef Cleaners as the best source for clean up crews.

  What is a clean up crew?  

  Most often, a clean up crew is thought of as being but a few herbivores or scavengers to simply eat algae and clean up left over fish food. I feel this is an over simplified view and most often does not take into consideration that we are striving for a Reef aquarium. It is my hope that by taking the effort to put this together, it will inspire or guide others to think outside of the coral box. After all, what is a reef? Surely not a bunch of rocks with some corals parked on top of it all. I enjoy all the "little people" as much or more than I do the coral species kept plus the fact that I wish to have an actual ecosystem that through its various animal and plant members can maintain itself. Each animal has its part to play in that role and in combination, makes for an easy to keep reef aquarium with minimal equipment and effort while providing me with the joy of seeing it all in action. Being that most all of the inverts and sponges are closer to the bottom of the food chain than say the corals and fish are, I also consider these animals to make up what one could call a very extensive "clean up" crew while providing food for other species as well. Since I am discussing food chains I need to stress the fact that all food chains with one exception (deep ocean vents) start at the bottom with plants or algae. The very item that caused us to consider buying a clean up crew to begin with. Yet once an aquarium does acquire a diverse clean up crew, it will most likely need to be supplemented with phytoplankton to ensure we keep as much diversity as possible.  In short, a clean up crew is a reef !

 Coral Reef Aquariums -  With this type of environment being the most commonly used, the clean up crew packages or kits are targeted toward such aquariums.  Far to often the incorrect species or types of animals are sold to new hobbyists who are unaware of the habitats or locations that the animals came from. This often leads to a great many deaths and problems as many of the species sold are not actually found within the habitats that we try to recreate. Even when the correct animals are made available, the recommendations as to how many of each species to be added to our aquariums at one time also leads to high mortality rates. I am always astounded to see a recommended stocking level of one snail per tank gallon size be used for a newly established reef aquarium. In a one hundred gallon aquarium, how are one hundred herbivore snails going to find enough to graze upon? Is this done out of ignorance or is this supposed to be a lesson about the survival of the fittest or luckiest as surely there will not be enough algae present to sustain such numbers.


  FISH -  I know of only one species of fish that can be considered truly beneficial, and by that I mean it performs such a good service that its contribution in keeping the majority of algae species in check far outweighs its contribution to dissolved nutrient levels.
Photo by Charles Raabe  Zebrasoma scopas - The brown scopas tang, the one fish species that I will always have in any coral display aquarium where algae must be kept under control.

  SNAILS  -  With the vast number of possible species that could be made available at any one time, you will need to learn of the various snail families and their species in order to make a proper choice. Since the number of species is so vast, I can not of course examine all of them per their suitability for use within our aquariums.  Instead I will discuss the most common families usually available and highlight a few species of each family.  By doing so, I hope you will then be able to make an educated selection when shopping for your clean up crew.

 Super Family - Turbinoidea
 Family - Turbinidae Astraeinae -  Please see this link for Identification purposes.

   The Astraeinae - Commonly called the Astrae snails.  This is as most snail families are, a very large group containing many species, not all of which are coral reef inhabitants.  The species shown is an Astralium calcar and is my first choice when looking for herbivores. This species and those with similarly shaped shells are best suited for our reef aquariums as their flat shape allows them to easily right themselves should they topple over. While this specific species may not always be available, any other species with the same shell shape or design will be suit your aquarium's needs.

   The Astralium okamotoi , has one of the most commonly shaped shells found within the hobby even though it is not a coral reef inhabitant. The tall coned shaped shells ensures that should they topple over, they will become firmly wedged in the rocky landscape and die a slow death if not found and uprighted by the hobbyist.  I never see this species or those shaped like it out on the coral reefs and are only found within the shallow sea grass beds keeping the sea grass blades clean of algae growth. Should they fall off their perch, with the flat terrain and abundant leaf litter, they easily right themselves.
   These species as well as a great many more are offered for sale not because they are suitable reef inhabitants, but because they are most easily collected. If given the task of having to collect herbivore snails I would much rather stand in knee deep water and pluck them off of the sea grass or other near shore areas in great numbers than to put on scuba gear and spend an air tank's worth of time fifty feet underwater on the coral reefs trying to find reef living snails that are most likely hiding deep inside the reef during the daylight hours.  This practice of collecting snails from shallow near shore habitats only ensures that we are offered a great many unsuitable species for our aquariums.  When researching  suitable species, please note their locations found as any of the subtropical species will not survive long in our very warm tropical aquariums. It is my hope that this article will give you the knowledge to be able to chose wisely.

  Super Family - Turbinoidea
  Family - Turbinidae Turbininae  - Please see this link for Identification purposes.
   The "Turbo" or "Turban" snails, also very commonly sold as suitable for our aquariums, which they are if they are suitably sized. The species shown reaches a maximum size of 15mm while other species easily approach 100mm. Not something I would want bulldozing its way through my corals and landscape. The link I have provided for this family will allow you to choose the correctly sized species for your aquarium.  Shown in the photo is a Turbo mazatlanicus , which averages in size between 5 - 15 mm.  Again, while this family of snails are good grazers, their usually large size limits their usefulness.

 Photo by Brian Plankis of Project DIBS  The "DIBS" Turbo snail ( Turbo argyrostoma. ) -  Of all the species of turbo snails, I would recommend this species for quite a few reasons.
 1. Due to their rapid reproduction they are excellent when starting new aquariums as the available algae will control their populations, ensuring you have a balanced population of snails.  For more information, please see this topic thread.
 2. The competition from the babies keeps the adult sizes smaller than the typical cold water turbos so they rarely disturb or dislodge corals.
 3. They spawn frequently producing many juveniles which can then be shared with other hobbyists. What better way to start in the hobby than by helping to take the pressure off of the wild stocks.
 4. They are a tropical reef species, making them suitable and long lived within our tropical reef aquariums.

 Super Family - Trochoidea
 Family - Trochidae Trochinae - Please see this link for Identification purposes.

   The "Trochus" and other members of this family can be suitable for our reef aquariums if once again, their shell shape is taken into account. Some species within this family are much more "squat" than others that resemble the tall pyramid shapes found within the Astraeinae family.

 Photo by Charles Raabe  A member of the Trochidae family, Stomatella varia. Not normally found for sale but is a very common find as a hitch hiker upon live rock.  An excellent herbivore as well as there be many reports of this snail species reproducing successfully within our aquariums.

 Super Family - Cerithioidea
 Family - Cerithiidae Cerithiinae - Please see this link for Identification purposes.

   The "Cerith" snails as they are commonly called are another suitable species for our rocky environments. It is not uncommon to find members of this family hitch hiking in with live rock and can be confused for being a predatory whelk. This is where your skill in being able to identify snail species will come in handy.  Shown is a Cerithium punctatum.

 Super Family - Cypraeoidea
 Family - Cypraeidae Erosariinae - Please see this link for Identification purposes.

 Cowry snails are usualy seen with mantles covering their entire shell  Very few species within this family are strict herbivores. A great many of them are omnivores, able to switch between algae and more meatier items such as corals or anemones. I consider the ringed cowry ( Cypraea annulus ) to be the only species suitable for our reef aquariums as it will readily consume both micro algae and many of the filament (hair) algae species while remaining small.  There are a few other species that are made available from time to time, but these become very large and would soon have your landscape laying in the sand.

 Super Family - Fissurelloidea
Family - Fissurellidae
- Please see this link for Identification purposes.
 Photo by Charles Raabe  The Scutus,  Slowly becoming available in the hobby but most often only found as a hitch hiker upon live rock purchases.  Some species get fairly large and would most likely not be suitable except for very large aquariums. The species shown in the photograph remains a small size and are all excellent algae grazers.  One word of caution - The black species gets quite large and there have been reports of it feeding on coral tissue once it has eaten all of the algae. The species shown above remains relatively small and has not been known to become a problem. 
 Photo by Steve Buehler  The Limpets, Belongs to the same family as the Scutus. There are a few species that can be found on live rock, but the majority of them are shore line creatures capable of withstanding exposure to air during low tides. If available, some of the smaller species could be suitable for our aquariums.

 Super Family - Neritoidea
 Family - Neritidae Neritinae Neritini - Please see this link for Identification purposes.

Herbivoures, but most types are intertidal and will climb out of the tank  Most Nerites are not suited for aquariums simply because they are inter tidal, moving above the water line and only returning to the water to feed upon algae. I doubt that any of the species made available would be of a suitable species simply because the collectors can easily gather them by their hundreds near the shallow shore lines.

 Super Family - Haliotoidea
Family - Haliotidae
- Please see this link for Identification purposes.

 Photo by Charles Raabe  The Abalone - Most species within this family are too large for a typical aquarium with one exception. The species Haliotis asinina , also know as the ass or donkey ear abalone remains relatively small compared to other members of this group averaging three to four inches in length. Still a fairly large snail and one that I would only recommend for the larger aquariums.

  Order - Polyplacophora - Please see this article link.

Harmless algae eater  The Chitons.  A very common hitch hiking find within live rock. Most species will prove to be harmless grazers and add a unique animal to your aquariums diversity.  I do not know of any sources for purchase or those who have successfully bred and raised them.

  You may have noted that the Nassarius species of snails is lacking, this was not an oversight but simply my view that with the use of live rock and its many scavengers, there is no need to keep such snails as they most likely will not find enough to eat, or will out compete the many other members of your clean up crew.

  For more information on snails please see my Hitch Hikers Guide to the Reefs.


I do not allow any of the free ranging species of crabs within my own aquarium system simply because they are all omnivores, capable of getting by on algae, but should they find that meatier items are easily available within your aquarium, such as snails, tube worms and a host of other inverts, they can become quite efficient little predators.  The hermit crabs are often sold in great numbers as members of a clean up crew package.  This may be fine for fish only systems that the crabs have little chance to be of harm, but within a reef aquarium that strives to keep a diversity of life, they can and will become very detrimental to the goal of maintaining any diversity of life.  These concerns apply to all crabs, including the popular "emerald" crabs sold for algae control.  The only crab species that I allow within my system are those that are commensals, never leaving their host coral or anemone.

 Cute for a crab, but still a crab!  Free roaming hermit crabs cause more trouble than they are worth over the long term. There are much safer alternatives for detritus and left over food clean up.  
  For more information concerning the crab species that are and are not reef safe, please see my Hitch Hikers Guide to the Reefs.


 As members of a clean up crew,  I would recommend only the brittle star species.  Most all other starfish are predators and do not belong within a reef aquarium setting. 

 Photo by Charles Raabe  A typical brittle starfish. Such starfish will usually pick a specific place to settle and will remain there, extending its arms in search of left over food or detritus while keeping its vulnerable central disc hidden and safe from predators.  The brittle starfish species can be found in any number of sizes, with most being an average that makes them suitable for our aquariums.  Please see the relevant section of my hitch hiker pages for more information on starfish species per their being reef safe or not.  A great many species of brittle starfish find their way into our aquariums as hitch hikers within live rock and at times, live sand.  Caution :  Just as with any marine family group, there are those members that do not belong in an enclosed aquarium system. The brittle starfish Ophiarachna incrassata (large green species) is a very active predator of fish. 
 Photo by Charles Raabe  The Mini Brittle Starfish - With the purchase of live sand and live rock, it is fairly certain that you will obtain any number of very small species of brittle starfish. Quite a few species will bury themselves into the sand leaving only their arms extended to catch passing food particles. It is unknown as to how they reproduce within our systems but they manage to do so.  If you do find yourself lucky enough to have a large population, I encourage you to share them with fellow hobbyists.
 Photo by Charles Raabe  Asterina anomal - Yet another commonly found hitch hiker that can prove to be a beneficial member of the herbivore clean up crew. With sufficient food sources, these small starfish can reproduce within our aquariums by casting off their arms which then form new starfish. Such a reproductive method is why they appear to have different sized arms at all times. Caution :  With the Asterina family having hundreds of members, and their being little studied, you may on the rare occasion find what appears to be the above mentioned species yet it will be a coral predator. If you do find what appears to be an Asterina anomal on a coral, it is best to remove it and all others that look like it. Again, I want to stress that this is a rare event and do not want to condemn all like starfish for the bad habits of a few members.

   Please note that the so called sand sifting starfish are not recommended simply because they, through their sifting of the sand are only doing so in order to find and eat the sand dwelling infauna that you paid for when you purchased live sand. The same can be said of any animal that actively sifts the sand such as some goby species.

  Shrimp :

  I would not recommend any of the decorative shrimp such as the peppermints or cleaner shrimp as they do prey upon other small invertebrates within a reef aquarium. The only members of this crustacean family that I allow within my aquarium are the pistol or snapping shrimp. By forming burrows under the sand and within the live rock, they are effective at removing left over food particles and detritus.

 Photo by Charles Raabe  The snapping or pistol shrimp make for an interesting member of any clean up crew. Although rarely seen once they have established a burrow system, they do however keep their areas cleaned of any food particles. Most species that end up as members of our clean up crew came to us by hitch hiking in with live rock.

 Photo by Charles Raabe  The Thalassinidean shrimp are also a very frequent find within live rock.  I would wager that a great many aquariums have a number of these shrimp yet do not know it as they are very cryptic, remaining forever within their live rock burrows.

  Sea Cucumbers :

   I doubt I would ever have a reef aquarium without at least one sea cucumber being present.  Having the surface of the sand bed kept clean is too good of a deal to pass up.  When selecting a suitable species, your aquarium size must be taken into account. I would recommend no more than one sea cucumber per seventy five gallons of tank space. Any more than that and you risk starving them to death.

 Photo by Charles Raabe   There are some species of sea cucumbers that I avoid simply because they are quick to expel and could kill my fish. For more information concerning species selections, please see this link.  While not a complicated animal to care for, there are a few concerns to take into consideration when adding a sea cucumber to your aquarium. Not being the quickest or brightest of creatures, any pump inlet that is not covered or protected will pose a very real danger to your sea cucumber. Keeping the inlet guards that should have come with your pump when you purchased it, in place, will prevent any such accidents from happening.
   You will also want to ensure that you do not have any species of fish that are known to be predators of sea cucumbers. Most Trigger fish, some Wrasses and Butterfly fish will nip at the tube feet of sea cucumbers. Although sea cucumbers are nocturnal, our rock landscaping usually does not provide enough protection to hide in and be completely safe from predatory fish.
   Other than those few simple precautions, a sea cucumber's only real danger within our aquariums is from starving to death. If you notice that your sea cucumber is slowly shrinking (getting smaller), then it would be a good idea to try and find it another home that can provide the amount of detritus and organics it needs to thrive.

 Sea Urchins :

  Not recommended for reef aquariums simply because they are very efficient at removing any and all life from our live rock. There are quite a few species that during their grazing, will consume all life that is found on what ever patch of rock they happen to be feeding on. Some species have been known to eat soft corals as well.
  Just as with all animals being considered for your aquarium, you should research each species for its suitability. Be aware that some species are venomous and can pose a health risk to you as well.

 The Worms :

  The unsung heroes of any clean up crew.  While some species are slowly becoming available for purchase, you will most likely get a variety of worms hitch hiking in on live rock.  Please do not assume that just because they are worms that they are some how harmful.  Even when large, most all species are very beneficial to our aquariums and their presence should be encouraged.
  Some of the most commonly found and most beneficial of species, there are of course a great many other very beneficial worms, both large and small that should be looked upon as the foundation of any healthy clean up crew. For more information please see the worm section of my hitch hiker pages.

 Photo by Charles Raabe   Eurythoe complanata  -  Probably the most commonly found worm and is a harmless scavenger, a benefit to our systems. It is my opinion that these worms are an excellent replacement for the use of destructive hermit crabs.

 Photo Credit :  Kelly   The Cirratulids, or better known as the hair worms.  Any number of species can be found within live rocks and live sand as they are indirect filter feeders living off of detritus and other small food particles.

 Photo by Charles Raabe   The Terebellidae or spaghetti worms. Yet another common hitch hiker and one of great benefit as they also inhabit both live rocks and live sand, only extending their feeding tentacles in search of detritus and other food particles.

 Photo by Charles Raabe   The Sipunculida worms or peanut worms.  One of the most commonly found worms living within live rock extending their feeding proboscis in search of detritus and left over food particles while keeping their peanut shaped body hidden within the rock.

  Sea Slugs & Nudibranch :

 Elysia crispata - The Lettuce nudibranch, eats a variety of large algae but seems to prefer the bryopsis filament algae. A delicate species and should only be kept by the more experienced hobbyist. 
Photo by Charles Raabe  Phanerophthalmus smaragdinus -  This species is an obvious herbivore yet it is unknown if it is a specialized feeder or not. At this time I do not know of any sources to purchase these slugs yet they can be found as hitch hikers on rare occasions.
   Aplysia punctata  -   This Sea Hare is commonly sold and is a species I do not recommend for our warm tropical aquariums as it is a subtropical to cold water species.

  Zooplankton :

  With the purchase of live rock and live sand, you are bound to obtain quite a number of tiny animals that if encouraged can not only be a benefit in helping to clean house, but if they themselves are encouraged to multiply can provide quite a bit of live food for your other pets as well.

 A few photo examples of the more commonly found animals that I encourage through the use of phytoplankton dosing.
 Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe
 Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe

  Meet Your SandBed's Clean up Crew :

With the purchase or collection of live sand, you of course obtain a great many animals that live within such sandy habitats. These mostly microscopic animals are what keeps our deep sand beds functional by providing not only the removal of organics, but in preventing the sand from forming clumps by their many microscopic movements through the sand. A great deal of live food is also produced in such sandbeds and yet another good reason to consider keeping as much diversity of life as possible.  A few photo examples of but a few sand dwelling animals :

 Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe
 Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe  Photo by Charles Raabe

  Stocking Methods and Levels for new Reef Aquariums :

Since it is most likely that a clean up crew, live rock and live sand will be purchased for a newly established reef aquarium, It would make sense that when doing so, the life that will be purchased be given their best chances to survive.  Their success will ensure your success in maintaining a reef aquarium and one that is more realistic.  Here is a brief stocking schedule that takes biology into account and ignores your wish to have a fully stocked reef aquarium by weeks end. Be patient and let the aquarium's biology find its balance through you properly stocking the aquarium and giving it the time needed to become a functional ecosystem. Please note that this is how I have done "it" and will continue to do so for all new aquariums that I may start. There are other methods of course which I feel do not fully take all of the life and its required time into account.

  Once all of the aquariums equipment is installed and the aquarium filled with salt water, then its time to get the biological ball rolling.  Just as with any ecosystem, its most important players are usually always the smallest. An easy way to think of it, is it being exactly what it is, a food chain. With bacteria being the most important and least appreciated members of your clean up crew as well as the beginning of that chain.  

  Sand bed - Being that it will be on the bottom of the aquarium, it should of course go into the aquarium first. How deep a sandbed is up to you as I will not try and address the pros and cons of having either a shallow dead sandbed or a deep live sandbed.  I of course prefer a live deep sand bed for the diversity of life that it brings to the aquarium as well as providing the proper habitat for other life forms and its denitrification potential. Remember now, this is a Reef aquarium not a coral display tank.  
  1.  Put a three inch layer of "dead" sand on the bottom of the aquarium.  This will become the base for the later addition of live sand.
  2.  Place your base rock on top of or down into this base sand, these will of course be the base for the later addition of live rock.
  3.  Leave all equipment running with the exception of the lights. There is no reason at this point to start growing algae when it will soon be covered over.
  4.  Take a one half inch long piece of shrimp meat and drop it into the tank.  This will be the source of ammonia needed to start the biofilms (bacteria).
  5.  Allow the aquarium to cycle which may take a few weeks. After one week, start doing daily tests for ammonia and nitrates. Once you can detect a nitrate level of "10", then you may remove what remains of the shrimp meat as having detectable levels of nitrates means that the initial bacterial biofilm is in place.
  6.  After the removal of the shrimp meat, allow the aquarium to run as is until you can no longer detect any ammonia. Be prepared to add your live sand and live rock as soon as possible once you have undetectable ammonia levels.

  After the initial cycle is complete:

  1.  Place at least another three inches of truly live sand on top of the base sand.  When I say "truly" live sand, I do not mean that wet sand in a bag that is sold as live sand. That sand is simply base sand that may, or may not have some bacteria on it. The live sand I speak of is loaded with a great many microscopic and not so microscopic sand infauna (worms, forams, pods and so on).
  2.  Place your uncured live rock on top of the base rock and form your landscape, trying to keep future coral placements in mind.
  3.  Turn on your lighting system to be run on a 12 hour day / night period.
  For the next four weeks take daily ammonia tests.  If you detect the ammonia levels starting to register or rise, you must take action to reduce the ammonia through water changes. This means that you should have plenty of salt mix and RO or distilled fresh water on hand. You can not allow ammonia to build up as it will very quickly kill all of that life you just added to the aquarium within the live rock and live sand.   

  After that first month or maybe more, your ammonia levels should become undetectable again and remain there. Now we wait for three more months and let the aquarium continue its cycle while allowing any algae to grow.  It is not going to be a pretty sight, but do not panic and start trying to control what has to happen. If you do start trying to prevent algae growth at this time, you are only going to delay the inevitable and make things harder for you and your aquarium later on.
  During this three month period :

  1. Study and familiarize yourself with saltwater chemistry issues such as phosphates, pH, calcium and so on.
  2. Plan out your coral and fish selections. This is going to take studying what each species requirements are.
  3. Read all that you can find the time to do so concerning reef habitats and reef aquariums.

  Now that those three months are over and your aquarium looks like a golf course, it is time to add the larger members of your clean up crew.
  Using a 100 gallon aquarium as a guide, I would add the following members of the clean up crew and in the stated quantities. The numbers of each species will of course have to be adjusted per your aquarium's size.

  1.  Herbivore snails - At least three different species for a total of 20 snails all together.  I know that it is usually recommend to add a great many more at one time, but what happens when too many snails consume all the algae quickly and run out of food? If after two months you note that the original 20 are not able to keep up with algae growth, then add ten more. Wait two months and add ten more if need be and so on.
  2.  A single sea cucumber -  Do not expect the sea cucumber to clean your sand's surface area quickly. It is going to take time. To add more than one will only ensure that one or all of them will slowly starve.
  3.  Brittle Starfish -  Five of the medium/larger species and/or twenty of the mini species.
  4.  At this time, I would start a daily drip dosing of phytoplankton to encourage copepod and amphipod populations.

  Wait another three months -  During this next three month period, the algae will get eaten, the water quality will be perfect and all the hitch hiking members of the clean up crew will be doing very well.  Coralline algae should start growing at this time also. Continue to study and planning out your coral and fish selections.

  Now that those additional three months are over, your aquarium is ready for its coral occupants. All the biology of the aquarium is balanced, the water is pristine and you have learned a great deal by your studying thus giving you the knowledge and the confidence to ensure your coral pets will be with you for a great many years.  Since corals place a very light bioload on an aquarium system, do not concern yourself that you may add too many specimens at one time. Putting four to five corals into your aquarium each month is acceptable.  

  Also at this time, you can set up your quarantine tank and put your first fish into it for its six week stay within the quarantine tank.  This is a must do procedure if you wish to have any hope at all in avoiding the introduction of parasites and diseases into your reef aquarium. For those aquariums that are at least 50 gallons or larger, I would suggest a brown scopas tang as your first fish. I have one within my 80 gallon display aquarium and it ensures that any and all filament (hair) algae and macro algae are kept under control.

 References :

   Mr. Eddie Hardy -  Hardy's Internet Guide to Marine Gastropods, 2007

   Dr. Ron Shimek -  A three part series on Polychaete worms -

  Eric Borneman - Concepts of stocking levels and the new tank, 2004

  Dr. Ron Shimek -  The Grazing Snails , 2004

  Charles & Linda Raabe - A Hitch Hikers Guide to the Reefs,  2007

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