Cultivating a thriving saltwater tank is both a joy and a challenge. You spend hours researching the perfect combination of species for your tank and pick out the ideal equipment to keep your tank running properly. Even after you get it all set up, your work isn’t complete – you then have to maintain the tank! Luckily, if you set your tank up correctly the first time you shouldn’t have to worry about too much maintenance but you do need to make sure your tank water quality remains high. A simple way to do that is to employ a clean-up crew in your tank.
A clean-up crew consists of snails, crabs, shrimps, and starfish in your saltwater aquarium that perform the following tasks:
· Clean-up detritus (non-living organic matter)
· Sift through your sand
· Keeps algae under control on a day-to-day basis
You can think of the clean-up crew as the janitors for your tank. Having a proper clean-up crew can help keep your tank sparkling clean while limiting the amount of work you have to do in terms of scraping the glass or picking algae of your live rock. However, there are some things to keep in mind when establishing your cleanup crew. In this article you will learn the basics about having a clean-up crew in your saltwater tank.
When Should I Introduce my Cleanup Crew?
If you are cycling your saltwater aquarium with live rock (as most saltwater aquarists do) then you will want to add the cleanup crew right after the cycle is complete (before you add fish). There will be die-off from the live rock and probably some algae from the cycle that will need to be cleaned up immediately. The clean-up crew can take care of this, helping to make your tank safe for your fish.
You only want to start off with snails and crabs as they are the hardiest -- starfish need an established food source in order to survive. Only after a couple of months (once you start to see a build-up of algae and detritus) should you add sand sifting starfish. Do not add all of your clean-up crew at one, however. You will need to add a few at a time to ensure that there is enough food to go around.
What Are the Best Species for my Clean-up Crew?
You really need a combination of species in order to do all of the tasks described in the bullets above. Some will sift sand, but not touch algae. Others will eat only a specific type of algae, but will not sift the sand. Obtaining a nice mixture will ensure that your tank stays clean.
Snails are particularly popular as members of a saltwater clean-up crew because they are very efficient. Marine snails come in a variety of sizes and each species has its own specialty in regard to what type of food it prefers to eat. Some snails eat algae off live rock and other tank surfaces while some reach into crevices or even sift through sand for food.
The most common snails for clean-up crew purposes include:
Turbo snails – Turbo snails are large aquatic snails that are particularly useful in eating algae. You need to be careful of these snails due to their size, however – they have been known to topple live rock. Turbo snails are particularly recommended for large aquariums because they can cover a large area in a short amount of time. If you do use turbo snails, make sure your live rock is secure and ensure that there is plenty of food for your snails to eat because they can go through algae fairly quickly.
Asterea snails – These are good snails for getting rid of brown and green algae from the walls of your tank, from your live rock, and from your substrate (they will not eat longer hair algae). They are also useful for smaller tanks because they do not grow larger than an inch. They do have problems, however, when they are flipped over as they cannot get back to their correct orientation and will die. If you see one on its back, you should flip it over.
Trochus snails – Trochus snails are very similar to Astereas in terms of their algae eating, but they can rescue themselves when they are flipped over. They also stay small, making them a nice addition to smaller aquariums like nano tanks.
Nerite snails – Again, this is a small snail (less than an inch) that is very good at eating algae off the tank walls. They will even come out of the water from time-to-time. They are also included in many hobbyists’ refugiums as they do great with marine plants.
Nassarius snails – These are one of the most interesting snails you can add to your clean-up crew (even though you will not be seeing much of them) because they target an area of the tank not addressed by the snails listed above - the sand bed. These snails actually bury themselves in the sand, stirring and sifting through it for food. They have a long siphon tube that protrudes from their front and you can often see it sticking out of the sand if you look closely. They will also come out of the sand bed to eat (again, a neat thing to watch) and will feed on many forms of detritus that other snails ignore. They do require a deep sand bed (at least 4”) for their survival and should only be added after the tank matures for several months after the cycle.
Crabs are perhaps the second most popular group of animals when it comes to forming a clean-up crew. Hermit crabs in particular are highly beneficial because they scavenge all over the tank, eating the food that is leftover by your fish. It is important to be careful when adding crabs to your tank, however, because not all of them are reef-safe.
The most common crabs for clean-up crew purposes include:
Red-legged Hermit Crab (also known as the Scarlet Reef Hermit Crab or the Red Reef Crab) – These crabs do an excellent job of scavenging and keeping algae under control (they will even eat hair algae which most snails avoid). They will also eat fish food. Red-legged hermit crabs stay small and are very hardy -- unlike most hermit crabs, they are also generally peaceful towards others in the tank. They can sometimes attack snails, although the Red Hermit Crab is much less likely to do this than the Blue-legged hermit. To mitigate this problem, toss some spare shells in the tank so they are not fighting the snails for theirs. As they grow and molt, they will look for new shells so it is important to offer these larger spares. They are considered reef safe.
Blue-legged Hermit Crab – Another popular crab that will relentlessly eat just about anything in your aquarium (algae, scraps of food, etc.) is the blue-legged hermit crab. They are reef safe (although some people do report they can kill specimens that are injured or dying), but have been known to be aggressive towards snails. Adding spare shells of a variety of sizes to the tank will help reduce this aggression. Their bright blue legs are stunning and they are a great addition to a reef tank.
Sally Lightfoot Crab – Again a relentless eater, the sally lightfoot crab will scavenge around the tank looking for bits of food or detritus and pick at algae constantly. They are generally considered reef safe although the larger ones have been reported to eat injured or dead fish if they cannot find other food sources. They also will crawl around on the corals a great deal, but this does not generally lead to problems. They get to be about 2-3” in size.
Emerald Green Crab (also known as the Emerald Mithrax Crab) – This crab stays fairly small (1.5”) and is considered peaceful and reef safe. The only time they have been known to munch on corals or fish is if their food supply runs out (you can supplement their diet with dried seaweed, fish food, and meaty foods). If well fed, they get along perfectly well with other inhabitants. It is also well known for its ability to eat bubble algae, something very few reef safe species do.
You may not think of shrimp as anything more than seafood, but they can actually be a valuable addition to the clean-up crew in your saltwater tank. These little creatures can get into the cracks and crevices that other invertebrates can’t reach to clean up detritus and uneaten fish food. Starfish also make great additions to the clean-up crew, not to mention their unique and beautiful appearance.
Other species generally used for clean-up crew purposes include:
Cleaner Shrimps – The most popular cleaner shrimps are the Pacific Cleaner Shrimp and the Scarlet Cleaner Shrimp (also known as the Red or Fire Shrimp). These shrimps do an excellent job of scavenging for leftover food, but they also pick parasites off of fish and are used to control saltwater ich.
Coral Banded Shrimp – Again a very popular scavenger and a very beautiful shrimp in general. They are considered reef safe, but some have reported that they kill fish. However, most people disagree with these reports saying they are aggressive towards their territory and will chase fish away, but they will not actually kill a fish.
Peppermint Shrimp – Make sure you get a true Peppermint Shrimp and not the similar looking Camelback Shrimp because only the true Peppermint Shrimp is reef safe. These shrimp are excellent scavengers and are one of the best methods for controlling Aiptasia.
Sand Sifting Starfish – These can reach sizes up to 12” so they should only be used in larger aquariums with deep sand beds. You also need to ensure there is an adequate food supply so they should only be added to established aquariums. They do an excellent job of sifting through the sand and turning it over. They also consume uneaten food and detritus.
How Many Specimens Should I Have in my Clean-up Crew?
There is no exact formula to decide how many snails, crabs or shrimp you can keep in your saltwater tank because every tank is different. Not only do you have to think about the gallon capacity of your tank, but you also have to think about what kind of fish and corals you have in the aquarium. Your best bet is to start with just a few specimens and to see how they fare – if they do well and you still have enough algae and detritus to support more, go and add a few more. Though there isn’t a one-size-fits-all formula, there are a few general rules for keeping invertebrates.
The general rules for keeping invertebrates in a saltwater tank are:
· 1 snail per gallon
· 1 crab per 4 gallons
However, these rules do not mean you can put 20 Nassarius snails in your 20 gallon aquarium. Instead, you want to mix and match the snails, crabs, and shrimps to get a good combination. Regarding how many of each species for the snails, consider these general rules:
· Asterea snails are usually kept at one per six or seven gallons due to their annoying habit of dying when they are flipped over.
· Trochus snails can be kept at as many as one per gallon.
· Nerite snails can also be kept at as many as one per gallon.
· Turbo snails should only be kept at one per every seven or eight gallons due to their size and extreme algae eating ability.
· Nassarius snails are generally kept at one per three gallons, but they depend more on the area of the substrate. If you have a tall tank then perhaps only keep one per five gallons.
These levels are for established tanks with a generous food supply of detritus and algae. In a newly cycled tank, you will want to start slow and then ramp up to your full stocking level or else they will all starve and you will end up buying a new clean-up crew.
As you can see, a clean-up crew can be quite expensive to establish and then you need to keep it up-to-date by replacing dead specimens. Take this into account when you calculate the cost of your aquarium. If you take the time to research the specimens you want to include in your clean-up crew, however, and make sure to provide plenty of food, your clean-up crew will help you to keep your tank well maintained.