By: Scott Zachow
Over the years, the term Clean-up Crew has been used loosely in the online communities so to start, I would like to offer what it may refer to when used. To most, clean-up crew is used to describe herbivorous invertebrates that help keep nuisance algae “in-check”. To others the term clean-up crew is used to describe the scavengers needed to populate a live deep sand bed to help to process decaying matter and to keep the sand bed aerated and alive. Both of these are important parts of the marine system and personally I don’t think it matters which one is used to describe the term. As long as you know what you’re seeking to add to your tank and for what reason (utilitarian or ornamental) you can add any definition to the term you want. What I intend for this article is to give some general ideas to the various “clean-up crew” participants that are available and their usefulness to the marine aquarium.
Herbivorous Algae Eaters
For most people the first thing added to their marine aquarium after the initial cycle is some herbivorous algae eaters. These are utilitarian additions for the sole purpose of trying to battle nuisance algae that shows its ugly face early in the game. Diatoms and Cyanobacteria are the 2 most commonly noted after the initial cycle of the system.
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For years, adding some type of hardy fish (usually Damsel Fish) to cycle an aquarium was common practice. Although effective for the captive environment the method was cruel and unnecessary for the fish. Many local stores trying to make a dollar will still recommend the inexpensive Damsel Fish to be used to kick start the bacteria populations needed to maintain the stable environment. Today, live rock is the best option for kick starting these populations and pushing the system through the nitrogen cycle. If live rock is not incorporated into the system, a raw piece of shrimp can be placed into a “sock” and placed into the tank for a week and then removed. The decomposing shrimp will help start the needed bacteria populations.
Other alga that may be encountered as the tank continues to develop and age is hair algae (Derbesia), bubble algae (Valonia) and other various green and brown film and filamentous algae. Snails have different capabilities to eat different algae, listed below is a list of the commonly available snails and what they are useful for eating.
Turbo Snails (Turbo fluctuousus, Turbo castenea) – Turbo snails are quick moving and a bit larger than other snails that we’ll discuss. They are hardy eaters and probably the best at attacking Derbesia and other filamentous algae. Due to the snails large appetites and the speed at which they eat, it is recommended that only a couple of them be added to the aquarium. Adding more than this will most likely cause starvation in the long term unless supplemental food is provided. Most of us want to rid the tank of nuisance algae, not introduce it to keep some snails alive.
Left: The larger, fast moving and voracious eating Mexican Turbo Snail. Right: Astraea Snails sometimes get flipped upside down and cannot turn themselves over, requiring assistance from the hobbyist.
Astraea Snails (Astraea tectum, Astraea phoebia) – Commonly spelled Astrea, these snails are handy at eating green and brown film algae that inevitably cloud our viewing panes. They are also helpful to add after a new marine aquarium has cycled and the Diatom bloom has started. Astraea snails are slow moving and slightly less desirable than others due to their inability to right themselves if they get turned upside down. Due to this prohibiting factor, when an Astaea is found upside down, the aquarist is forced to help them over which can be a tedious task. Although they are useful for film algae, due to their inability to right themselves it is recommended to only put 1 per 5 gallons of water.
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Diatoms are commonly brown rust colored algae that bloom in the early stages of a maturing tank or in mature tanks that have experienced a lack of care for some time. It is highly nutrient driven in that reducing the level of said nutrients will succumb the bloom. Since new systems experience a high level of nutrients as it continuous through the initial nitrogen cycle, new systems almost always experience this unsightly bloom. The film can cover everything, turning your beautiful coralline covered liverock into brown rock and the same for your bright white sand bed. Rest easy, the bloom will eventually pass. It is important to note that no Snail should be introduced into the aquarium until the cycle is complete and the levels (ammonia, nitrite, nitrate, etc.) will support their long term existence.
Trochus Snails (Trochus sp.) – Available cultured; Trochus snails are in the reach of every aquarists and should be included in any algae eating livestock package to help control nuisance algae. Trochus Snails eat a variety of aquarium algae from filamentous to film, especially diatoms, and do not grow large like the Turbo Snails making them an excellent addition. At younger ages, Trochus Snails also often culture and lay eggs in captivity. You will typically not see the eggs hatch because they quickly become natural food for your tank. You could easily place 1 Trochus Snail per 2-3 gallons of system volume.
Trochus Snails, available cultured and excellent algae eaters.
Nerite Snails (Nerita and Neritina) – Another common egg layer, Nerite Snails have quickly gained in popularity over the years for their ability to tend to nuisance algae especially on plants and macroalgae. Nerites at times need to come out of submersion so they may be better suited in tidal displays. Their ability to clean algae from other desirable plants and macroalgae make them excellent refugium candidates and could be added at 1 per gallon of refugium volume.
Stomatella Snails (Stomatella varia) – This snail is typically not purchased yet a very common and very prolific hitch hiker. The Stomatella is fast moving compared to other snails and has only a very small shell in comparison to others. Almost any reefer that has purchased an amount of liverock and gazed at their tank at night has noted an abundance of Stomatella Snails that they have never seen before, as this is a nocturnal herbivore. Due to their rapid reproduction, some people consider there a nuisance and they can be but fear not, there are many other reefers that would love to have a few if your willing to catch them and take them to local club meetings.
2 small Stomatella Snails, note the very small shell.
Bumble Bee Snails (Engina mendicaria) – These Snails should be avoided in the common reef aquaria due to their predatory nature to eat sand bed fauna. They simply lack the ability to eat algae although they are commonly sold as snails that will do such. Since these predators are likely to eat the worms and other desirable life one would want in a tank with a thriving deep sand bed, these snails should be avoided.
Margarita Snails (Margarites sp.) – This is another snail that is available and sold to aquarists as a tropical herbivore snail that would be a beneficial part of a “clean-up crew”. On the contrary, these snails are temperate snails and will not survive in a typical reef system kept at 80 degrees Fahrenheit. Sometimes common Turbo Snails may be misidentified as Margarita Snails but since we are not likely to make a positive identification, they too should be avoided.
Left: The very colorful Bumble Bee snails can be enticing, but should be avoided due to their predatory nature. Right: Margarita Snails should also be avoided as they are a temperate snail.
As mentioned at the beginning of this article, “clean-up crews” may also mean life that is necessary or beneficial to deep live sand beds. Since some snails should only be kept with deep sand beds but too are herbivores, I have decided to list these in this section along with other desirables for a sand bed.
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Sand bed fauna is necessary to keep a sand bed aerated as well as to help push detritus through the different depths where it can be processed by said fauna and bacteria. Due to expected life spans of some fauna and the predatory fish that may be kept in an aquarium with them, it is necessary to replenish the life in your sand bed occasionally; some people suggest that once per year is best.
Cerith Snails (Cerithium) – These snails are very active eaters that will help control outbreaks of nuisance film algae, especially diatom outbreaks in new aquariums. The added benefit to these snails is they are also live sand bed agitators, but do not have to be kept exclusively in aquaria with sand beds; although it is recommended. The Cerith snails are also long lived in captivity, which also makes them great candidates for the reef aquarium. They stay reasonably small and will not bother others kept with them in the reef. The amount of Cerith snails to add to your aquarium is dependant on the amount of food available to them; just like all snails. 1 per 5 gallons of water would be a good start.
Nassarius Snails (Nassarius vibex) – Nassarius snails are excellent additions to a tank or refugium with a deep live sand bed. These snails will bury themselves under the substrate until feeding time when they quickly emerge. This activity provides excellent agitation to the sand bed and stirs the top layer time and time again. Nassarius snails feed on carrion and other natural waste in the aquarium and will also eat on brine and mysis shrimp when fed to the aquarium. The main purpose in the aquarium is to keep a sand bed agitated and to help remove waste that builds on the surface of the sand bed. These snails are often mistaken for Ilyanassa obsolete but this can be visually determined as the Nassarius snails have a groove in their aperture that the Ilyanassa obsolete does not have. The Ilyanassa obsolete are also larger than the Nassarius vibex. I would recommend 1 Nassarius vibex per 2 gallons of water, only in an aquarium with a deep live sand bed. Tall tanks would alter this recommendation.
Recommended for any tank with a deep sand bed, Nassarius Snails bury themselves in the sand until feeding time.
Worms (Polychaete annelid) – There are many, many different types of Polychaete worms and for possible identifications, I will refer you to Dr. Ron Shimek 3 part articles on them in the references below. When one encounters a worm in the reef aquarium, it is commonly referred to as a Bristle Worm or Fire Worm and for the sake of this article; we’ll leave it as just that. The things to note is that these worms whether hitch hikers or deliberately purchased, are very beneficial members of “clean up crews” in tanks with live deep sand beds. They are excellent scavengers and excellent agitators for the sand bed helping to push detritus through the different layers of the bed. Most of the time, purchasing a large quantity of good quality cured liverock will provide enough Polychaete annelids to the aquarium but if desired they can also be purchased from some Internet sites.
The Crabs – I have opted to place all crabs in this one grouping for one simple reason, I do not recommend them as a part of any clean up crew. Crabs are opportunistic omnivores, that is they will eat other members of your clean up crew if they have the chance. Some people say that Blue-Legged Hermits are ok; some say that Scarlet Hermits are ok… I say that they can be problematic at any point so it’s best to avoid them all together. If one has a tank without any snails, crabs can be introduced into an aquarium fairly safely and they do make pretty good scavengers. My recommendation here would be to try and find some small crabs that stay small to ensure they don’t become problematic.
In a lot of cases, one may choose to add a variety of all these clean up crewmembers in their aquarium and a mixed variety is probably best. As long as enough food is provided these guys will provide good service for a long time. Whether your clean up crew needs are for nuisance algae or utilitarian for a live sand bed, choose the members wisely with the information provided here. Since most places sell clean up crew packages that contain a mix of snails and crabs it is best to avoid such package deals. There are many online shops that will allow you to pick and choose your own package items from which you can choose suitable members for your tank.
Reef On!
Scott Zachow
References and Additional Reading:
Calfo, Anthony and Fenner, Robert. 2003. Reef Invertebrates.
Reading Trees, Monroeville, PA. 399 pp.
Nassarius vibex and Ilyanassa obsolete – Reefland.com Forum Search
http://www.reefland.com/forum/showpost.php?p=95938&postcount=17
Polychaete annelids – Dr. Ron Shimek 3 part series.
http://reefkeeping.com/issues/2003-03/rs/index.htm
http://reefkeeping.com/issues/2003-04/rs/index.htm
http://reefkeeping.com/issues/2003-05/rs/index.htm
Pictures courtesy of Seacrop