A clean-up-crew (CUC) is a collection of utilitarian invertebrates and fish that are added into a saltwater aquarium with the specific intent of helping scavenge the tank for detritus, clean up leftover food, and graze on nuisance algae. Ultimately, these animals play a critical role in the enclosed aquarium ecosystem. Think of it sort of like a "keystone" species, without the clean-up crew everything else in the tank is worse-off or unable to thrive. 

Clean-Up-Crew Animals For Beginners

Algae Eating Snails Carnivorous Snails Algae Eating Crabs Omnivorous Crabs Cleaner Shrimp Others Fish
Bumble Bee
Emerald Crab Hermit Crabs - All types Skunk Cleaner
Blood Red Fire Shrimp
Tiger Conche

Sand Sifting Gobies


While there are a variety of additional clean-up-crew animals available in the hobby, these animals are listed specifically because they are the BEST choice for your new saltwater aquarium owners. There are a handful of additional animals like sea stars, urchins, and sea cucumbers which can be very effective but are not the best choice for a brand new aquarium and/or first-time tank owner. These specialized clean-up-crew critters have more specific dietary requirements and can be a bit more sensitive. 

If you would like to learn more about each of the particular species listed above, we have a detailed article linked below which may help you decide exactly which options you want for your tank.  Keep in mind the idea is to add some animals from each of the various categories to target different areas of the tank.

Learn More: Which Clean-up Crew Critters Should You Have In Your Reef Tank?

What & Where They Clean

Each of the clean-up-crew animals has a niche based on their particular diet and area of the tank they will target. They will clean up leftover food, decaying organic matter (dead animals), fish waste, and algae. They can scavenge the surface of the sand bed, sift through the sand bed, clean the glass, and scavenge among the rocks. Pretty much anywhere you put the animals, they will go to work without discretion.

The Limits Of A Clean-Up-Crew

CUC animals do a great job supporting your efforts in keeping the tank clean and healthy but cannot do it all by themselves. Think of them like teammates that "fight the good fight" alongside you. Filtration and maintenance are still a critical part of keeping your aquarium looking good and healthy.  

  • They cannot get rid of serious nuisance algae problems 100%
  • They won't eliminate the need to scrape your glass walls
  • They cannot keep the sand bed clean all by themselves

Common Mistakes 

Too much too soon: Clean-up-crew animals need food to survive. If the tank is still very new with very little algae and food waste then you need to be conservative with what you add.  It's not a terrible idea to gradually increase the clean-up-crew as you stock your tank. With more fish comes more food and waste which also means more nuisance algae will grow. You will be better able to support a larger population of CUC animals with more algae and food waste.  If your CUC animals starve and die in the tank right away, you are only creating more problems for yourself and possibly creating a toxic environment if ammonia and/or nitrite shows up.  

Too little too late: If you allow algae and waste to stack up without any clean-up-crew animals, you might find it tough to recover. Start adding clean-up-crew animals early in the game but don't overdo it. It's best to be conservative at first and you can always add more if you need them. 

Expecting too much: A CUC is most definitely not a silver bullet. These animals will not replace the need for regular maintenance. 

Not replenishing your CUC: Clean-up-crew animals don't live forever and will require replacement over time. Some live longer than others but adding a few new snails and crabs once a year is a pretty common practice to ensure your clean-up-crew remains robust. 

When To Add Your CUC

Some hobbyists have strong feelings about when exactly is the best time to add a clean-up-crew animals. It is a delicate balance that will be very particular to your tank. Most will agree it is safe to start adding CUC animals at the first sign of nuisance algae growth in the aquarium.  Just don't wait too long and be sure you're manually cleaning the tank all the while.

BRS Recommended Clean-Up-Crew For Small Aquariums

Adding a good variety is the key to an effective CUC.  Here is a great place to start for aquariums up to +/- 20 gallons.  If your tank is larger, you have room for more and an even greater variety, simply add more as your tank matures.  

  • 5 herbivorous snails
  • 5 carnivorous snails
  • 10 small hermit crabs
  • 1 cleaner shrimp

When it comes to utilitarian fish that graze upon algae in the tank, you have to be a bit more careful.  You want to be sure your aquarium is large enough and well established enough to support that animal. Something like a tang is going to get quite large and should not be kept in tanks smaller than +/- 70 gallons. Sand-sifting gobies can quickly starve in smaller tanks and can make a mess by stirring up large areas of the sand bed constantly. Rabbitfish are excellent algae eaters but require a tank of about 40 gallons and are venomous. Blennies are great fish to use in a smaller tank but should only be added after you have algae growing in the tank and you need to be sure to support the fish's diet with herbivorous foods like seaweed. 

Replenishing Your CUC

Pay careful attention to your tank, if you see more algae, add more algae-eating animals. If you notice detritus starting to build up, add more scavengers and carnivores. A dirty sand bed might be solved with a sand sifting goby. If you notice a whole bunch of empty shells on the sand, you likely need more hermit crabs and snails to replace those that have died. It's just an ongoing part of keeping a saltwater aquarium.