“Clean-Up crews” or “CUCs” are a vital part of any reef tank or FOWLR system. These crews are comprised of snails, crabs, shrimp, starfish, urchins, and sea cucumbers that help to eat and break down uneaten food, waste, tank pests, and pesky algae. They aren’t as flashy or as colorful as some of the fish or coral you may have, but CUCs will help to keep your ecosystem functioning properly.
When you are doing the initial setup of your tank, you can hold off on adding your clean up crew; a newly established tank will not be able to support them. Once you hit the 2-3 month mark, you should be able to start adding them. The organisms you add will depend on the needs of your tank, but there are a few basic members you will always want to have in your tank.
First, consider adding some small hermit crabs and Brittle Starfish that will be able to get into tight spaces and help clean up any uneaten food. Next should be snails to help keep your algae under control. Oftentimes new tanks experience algae blooms as they grow and snails like the Trochus Snail and the Bumblebee Snail will help to keep them manageable so you aren’t having to clean the glass every day. Other members of a well rounded clean up crew could be a Peppermint Shrimp to help control Aiptasia. In addition to keeping the glass and aquascape clean, consider adding some sand sifters like Sea Cucumbers or a Sand Sifting Starfish to help keep the substrate stirred up and oxygenated. Sand sifters should be added later on as your reef tank and it’s sand bed mature.
While Clean-Up Crews are helpful, there are a few things to be mindful of when it comes to the short and long term health of your tank. Some of the larger CUC members, like the Pincushion Urchin can disturb and knock over corals and unattached frags, so make sure the corals and frags are glued in where you want them prior to adding urchins. It is not uncommon to see Urchins carrying around and wearing pieces of corals and shells they’ve found along the reef. Something else to make note of, is that as an aquarium grows, the clean up crew will need to be replenished. It is best to add snails and hermits on a regular basis, as oftentimes their absence isn’t noticed until after a problem (like hair algae) appears. When adding to a clean up crew in your fish tank, don’t forget to consider what kind of fish you have as some species will eat shrimp, crabs, and other invertebrates.