Once your saltwater tank has been running for a number of weeks you will inevitably encounter nuisance algae and detritus build-up.
This cannot really be avoided but you can help to keep on top of it by adding a ‘clean up crew’ to your tank.
Generally shortened to ‘CUC’ in the hobby, your clean up crew will feast on various types of algae, uneaten fish food and fish waste.
Some will help keep your sandbed clean by grazing for minute food particles on the surface or burrowing through the sand and helping to turn it over, preventing pockets of detritus build-up.
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Clean Up Crew Critters
Let’s take a look at some of the critters that make up the best clean up crew for a saltwater tank.
Before you add any though, be aware that some of the fish you have, or intend to get, may make a meal of your critters. Puffer fish, for example, will quickly clear a tank of any crabs, snails or shrimp and certain wrasses will happily devour nudibranchs.
Also, do not add too many clean up crew critters to a new tank where there will be little for them to eat. The size of your clean up crew should grow over time as your tank matures.
Snails
Algae-eating herbivorous snails are among the most popular and readily available clean up crew critters. The ones to look for belong to the families Astraea, Turbo, or Trochus.
All will happily feed on micro-algae films that build up on your rocks and glass.
Other snails, like the nassarius snail, are carnivorous and will primarily eat uneaten fish food and waste but will also take care of any dead creatures that, if left unattended, will pollute the water.
Cerith Snail
The Cerith snail is the unsung hero of the clean up crew world and probably one of the first you should add, particularly to a new tank. All new tanks go through an ‘ugly’ phase where nuisance algae build-up due to nutrient imbalances.
The Cerith snail will happily eat diatoms which are one of the first of the nuisance algae to appear in a new tank. They will then go on to eat both micro-algae films and food waste.
Nassarius Snail
The Nassarius snail is often called the Vampire snail and for good reason. They dwell in the sand and most of the time all you can see is their small proboscis poking out of the sandbed. That is until food is added to the tank or something dies…
Then these carnivorous snails will ‘rise up’ from the sandbed and head in the direction of any food or dying matter.
As they live in the sand most of the time and tunnel through it they have the added benefit of helping to turn it over.
Turbo Snail
Turbo, Tectus, and Astrea, are often all sold under the Turbo name, and all these algae-eating snails will help clear algae from the sand, rocks and glass.
Conches
Fighting Conch
Small conches are another great addition to your clean up crew. Conches like the Tiger and Fighting Conch will eat any detritus that builds up on or in the sand as well as leftover food and algae.
Crabs
Hermit Crab
Hermit crabs are definitely one of the more interesting critters you can add to a saltwater tank.
The best species to add are the blue-leg hermit crab, the scarlet hermit crab, the red-leg hermit crab, and the blue-knuckle hermit crab. All are small and will eat leftover food and algae.
Whilst hermit crabs have been known to kill snails (so they can occupy their shells) you can minimise this risk by adding a good selection of empty snail shells of different sizes so the crabs can ‘move home’ as they grow.
Emerald Crab
The Emerald crab is prized in the hobby for their liking for bubble algae. Notoriously difficult to get rid of, bubble algae can become a real problem in a reef tank.
A single emerald crab in your saltwater tank will make short work of any bubble algae. Take care though as they have been known to pick at and destroy some corals. Try to get a female as they are less aggressive and make sure it is well fed.
Shrimp
Cleaner Shrimp
Cleaner shrimp are a fascinating addition to any saltwater tank but they do not, in fact, help clean your tank.
Rather they remove any parasites from fish that are passing by. They will also clean inside the mouth and gill coverings of the fish helping prevent disease.
They have bags of personality and will happily clean your hand as you carry out routine maintenance inside the tank which can get a bit annoying!
Peppermint Shrimp
Peppermint shrimp are usually added to a saltwater tank to get rid of aiptasia, that knotweed of the marine tank world.
They are sometimes a bit hit-and-miss at that job but always worth a try. Make sure you get the true peppermint shrimp, Lysmata Wurdemanni, as there are many look-alike varieties that won’t eat aiptasia.
Otherwise they will eat virtually anything you add to the tank to feed your fish.
They are nocturnal though, so you may not see a lot of them.
Miscellaneous
Sea Urchins
The most popular of the urchins added to a saltwater tank is the tuxedo urchin (Mespilia globulus). Others include rock urchins, long-spined urchins (pictured above) and pencil urchins.
They will eat most types of algae including stubborn species like green-hair algae and turf algae.
They can get quite large though and may dislodge small corals that aren’t fixed down properly. Some of the long-spined urchins also like to decorate themselves and may end up wearing your precious corals as hats!
The spines of this species contain irritant toxins so be careful not to spike yourself.
Sand-sifting Starfish
Sand-sifting starfish burrow just below the surface of the sand and help to keep it clean and turned over as they move through it.
They do require a mature sandbed though and should never be added to a new tank.
Sea Hares or Slugs
Usually bought to get rid of stubborn hair algae, sea hares will often then starve once the algae has gone. It is therefore best only to get one if you have an arrangement to return it after the algae has been removed.
Nudibranchs
The most common Nudibranchs added to a saltwater tank are done so to eradicate a particular problem.
The Blue Velvet Nudibranch (pictured above) consumes flatworms and will quickly eradicate them from your tank if you have a problem.
The other commonly used nudibranch is the Berghia Nudibranch which eats aiptasia.
The problem with adding nudibranchs to your saltwater tank is that they will starve once the flatworms or aiptasia have all gone but you may be able to return the nudibranchs to your fish store or pass them on to another reefer.
We hope you’ve enjoyed our article on the best clean up crew for a saltwater tank. Please feel free to add your own favourites to the comments below.
Clean Up Crew for a Saltwater Tank FAQs
When can I add a clean-up crew to my saltwater tank? – You should only add a clean-up crew when they have something to clean. This means when your tank begins to enter the “ugly phase”.
So-called when diatoms first start appearing on your sandbed and rocks and nuisance algae starts to appear.
How much clean-up crew do I need? – Obviously, that will depend on the size of your tank, how many fish you have, etc. It also depends on the age of your tank as newer tanks have less waste to clean up.
A general rule would be to add one clean-up crew member for every 10 litres of tank volume for newer tanks and two members for established tanks.
What is the best clean-up crew snail in saltwater? – In our opinion, the humble Cerith snail is our go-to clean-up crew member.
Not only will they tackle diatoms but will go on to tackle algae on the rocks and glass as well as uneaten fish food and waste.
What is the best clean-up crew fish in saltwater? – Blennies and Tangs will eat many types of algae. Our favourites are the Lawnmower and Starry Blennies. Not only are they great clean-up crew members but they look cool and have bags of personality.