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The Beginner Guide To Clean Up Crews

Table of Contents

I) What Is A Cleanup Crew?

A cleanup crew (CUC) is a group of invertebrates that you add to your aquarium that help remove algae and detritus.  A CUC is important because too much decaying matter in your aquarium can lead to ammonia, nitrate, and phosphate spikes which can poison your livestock or create an unseemly tank.

A CUC can help, but you need to understand the different members of the crew and each of their strengths and limitations.

1) What Does A CUC Clean?

  • Algae- There are many different types of algae that will grow in a saltwater aquarium.  Some algae is common and easy to remove such as film algae that grows on the glass and diatoms which always show up during a cycle.  But there are also nuisance algae that can quickly take over your tank and suffocate your coral.  Different members of a cleanup crew will attach and eat different types of algae.
  • Poop- Everybody poops, including all of your livestock.  The hope is that it will get picked up into the water column and pushed into your filter.  But sometimes it falls into the substrate, caves, and live rock crevices.  So certain members of the CUC will help stir the sandbed and even consume poop.
  • Food- Overfeeding is super common amongst hobbyists, and can lead to increased phosphates and nitrates.  If you feed too much or too quickly, food will sink to the bottom or get caught in the live rock, thus becoming trapped and breaking down into ammonia, nitrite, and nitrate.  Whether you feed meaty foods or algae to your fish, there are members of the CUC that can help.
  • Dead Livestock- Fish and invertebrates will occasionally die.  Best case scenario is that you are able to notice the death quickly, and remove the specimen.  But sometimes a fish or snail disappears and you don’t even know it.  There are CUC members that will help by consuming the dead livestock.
The Flipper algae scraper

2) Members Of A CUC

  • Snails– There are snails for every occasion!  Ones that clean your glass, ones that eat leftover food, ones that eat dead fish, and others that graze your live rock for nuisance algae.  Some snails can flip themselves over when they fall, others need your help!  Some are large with voracious appetites and can starve quickly.  We’ll give our snail recommendations below!
  • Crab– Hermit and Emerald crabs are probably the most popular members of a CUC.  But a word of caution.  If you plan on keeping corals, crabs can nip at and eat them.  The Emerald Crab is exceptionally notorious for this.  I personally only use Hermit Crabs, because they are much easier to remove if caught nipping at my corals. Crabs are great for eating leftover food, and are also known to chomp down on certain types of nuisance algae.
  • Shrimp– Not only are shrimp a fun part of any CUC, they are also great detritivores and will actively go after meaty aquarium foods and leftovers.
  • Conch– These omnivores are great for keeping your sandy substrate aerated and clean, as well as munching on algae near the bottom of the tank.  Their long mouth  can stretch quite far, and is often compared to an elephant’s trunk.  Good for any size aquarium, they do eat a lot so in a small tank they may require supplemental feeding.
  • Starfish/Brittle Stars– While these can be tricky to keep in a home aquarium, there are certain species that are great members of a CUC.  Sand Sifting Starfish will help keep your substrate clean and aerated, and Brittle Stars will climb around your live rock and each various pieces of detritus.
  • Urchins– These can be good additions to your aquarium, as long as your aquascape is cemented/epoxied together tightly, and there are adequate hiding spaces.  Most species are herbivores and will crawl around your live rock eating algae, while others will also pick at pieces of meaty food.
  • Sea Slugs/Cucumbers– These are for experts only.  They are beautiful, but if they die, they can be poisonous and kill virtually everything in your tank.  So I would never, ever recommend a beginner to get one!  I won’t even get one! 
Gravel Vacuum
Gravel vacuum- primary "CUC" member

3) When To Add A CUC

Don’t add a CUC immediately.  Wait until the tank is cycled and you are noticing adequate algae growth.  I always recommend adding a small amount of CUC members at a time, just to make sure there is enough food for everybody.  You can always add more later, but not the other way around.

So how long should you wait?  At the very least, wait until your tank has completely cycled.  As soon as you start adding fish and feeding them, your bioload will increase.  And with the increase will come more algae growth and detritus.  There are several online companies that sell starter packs based on the size of your tank, and your LFS can also be a great resource.  I’ll give you my recommendations below.

II) How To Choose A Cleanup Crew

Ask yourself, “What needs cleaning?”  and go from there.  When you setup a new tank, typically you are dealing with some basic algae issue, as well as extra food and fish waste.  But as time goes on, you may encounter some specialty problems that will need to be addressed by more and/or different CUC members.  Here are a few things to think about when deciding on your CUC.

1) Size of Aquarium

Most beginners will have smaller tanks, let’s say around 15-40 gallons.  The larger the tank, the more CUC members you are going to need.  Here’s my general rule of thumb:

  • For a 20-gallon tank, I typically start with 10 snails, one cleaner shrimp, and two hermit crabs.  Five snails are herbivores and will clean the glass and rock, and the other five snails are detritivores and live in the sandbed and eat extra food and fish waste.  Obviously this is just a starting point. 
  • For example, my current 24-gallon aquarium has about 15-20 snails total, one cleaner shrimp, and one conch.  That’s it. I don’t have any hermit crabs because my 24 gallon aquarium is dominated by LPS corals and softies, and I don’t want the crab to pick at them.
Fluval Evo 13.5 gallon
A popular beginner tank at 13.5 gallons

2) Bioload

When you are starting out in this hobby, it is hard to judge what others would consider a small vs. a large bioload.  But as you get more experience and start testing your water, you will start to understand that a certain amount of livestock causes your phosphates and nitrates to spike, and you may even start to notice more frequent nuisance algae outbreaks.  

What all contributes to your bioload?  Fish waste, fish food, coral waste/food, anemone waste/food, etc… You get the picture.  Nutrients can build up quickly in your tank, so my advice is to start slow, give your filtration time to catch up, and only add a small amount of livestock at a time.  That way when you do inevitably see a spike in your phosphates and nitrates, you’ll be able to apply the brakes more quickly.

3) Substrate

Whether or not you decide to have a sandy substrate will have a huge impact on your CUC.  If you choose to have a bare bottom tank, then there are certain members of a CUC that you won’t need and won’t be able to keep alive.  For example Sand Sifting Starfish, conches, and many carnivorous snails (Ceriths, Nassarius) need a sandbed to survive.

But on the other hand, if you choose to with a bare bottom tank, it will be much easier to keep things clean.  Instead of fish waste and food getting caught in the sandbed, if will just sit on the glass bottom waiting for you to use a baster or small powerhead to kick it into the water column and into the filter.

Overall, a bare bottom tank is much easier to keep clean, and will require a smaller CUC.

Fiji pink sand in 20 lb bag with close up of grain size
CaribSea Fiji Pink Sand

4) Nuisance Algae

Nuisance algae can be a huge pain and something every hobbyist deals with at some point.  If not contained early, it will easily spread and cover all of your live rock.  Hair Algae, Turf Algae, and Bubble Algae are some of the most common types.  It is often challenging to find a member of the CUC that will consume these.

For example, I’ve found that a Turbo Snail will be able to keep hair algae at bay early on, but if the algae grows too big, then the snails will ignore it.  

Let’s take Bubble Algae as another example.  This stuff spreads rapidly, and no snail eats it.  But Emerald Crabs are known to eat it, but also your corals!  So while an Emerald Crab may be a good addition to contain an outbreak, you may come to regret it later when the crab kills your prized coral!

The moral of the story?  You need different members of the CUC for different types of algae, and even then it might not be enough.  Usually when there is a nuisance algae outbreak, something is off with your tank.  Maybe it’s overfeeding, too much lighting, or a sandbed in need of a vacuum.  Whatever it is, find the right CUC to add but also tackle the problem manually.

III) Best Cleanup Crew For Beginners

Well, we’ve reached that part of the blog where I give you my recommendations.  We’ve already gone over the various members of the CUC team, but not all of them will be right for a beginner, and there are often a lot of different species within each category. So let’s get to it!

1) Algae Eating Snails

Turbo Snails

By H. Zell - Own work, CC BY-SA 3.0,

There are various types of Turbo snails from Mexican, Carribbean, Chestnut, and Zebra, and while they are different, they are similar enough to group them together.

Turbos are large snails that enjoy grazing algae off of live rock, and sometimes glass.  They are big eaters so if there is not enough algae, you may need to supplement feeding with seaweed or other algae products.

These snails cannot right themselves when they fall, so be on the lookout and flip them back over when need be.

They can grow quite large, and are known to dislodge or break stoney corals, so just be careful!

Trochus Snails

Slightly smaller than Turbos, the Trochus Snail is also a voracious algae eater, and they have a unique ability: they can right themselves when flipped on their back.  That’s a nice feature that will help you keep your hands out of the tank.  I have found my Trochus Snails to spend a bit more time on the glass, and not as effective vs. nuisance algae

One big difference between Trochus and Turbos, is Trochus snails won’t break your corals or destroy your aquascape.  They don’t get as big and aren’t as powerful as Turbos.

By H. Zell - Own work, CC BY-SA 3.0,
CaribSea Life Rock Shapes
CaribSea Life Rock

Astraea Snails

By Jan Delsing -, Public Domain,

Another great algae eater, Astraea Snails are great for cleaning your live rock.  They are known especially for feeding on hair algae, cyanobacteria, and diatoms, all of which you will probably encounter from time to time.

Nerite Snails

By TheJammingYam at English Wikipedia, CC BY-SA 3.0,

These little guys are great for scrubbing film algae off of the glass.  While not big in size, if you are having to scrub your glass every couple days, pick up some Nerites and they will help.

2) Carnivorous Snails

Nassarius Snails

By H. Zell - Own work, CC BY-SA 3.0,

These are some of my favorite snails, and boy can they haul.  They spend their lives buried in the sandbed with a large tentacle peeking out waiting for food.  These snails are voracious detritivores, and will also help aerate your sandbed.  They can also help consume dead livestock, and are quite easy to keep in a home aquaria.

Cerith Snails

By H. Zell - Own work, CC BY-SA 3.0,

Similar to Nassarius, Cerith Snails spend most of their live in the sand, helping to keep things aerated.  They have a long spiral shell, and will consume excess fish food, waste, and even algae.

It’s good to have several of these snails because their long, thin shell makes them better able to get into tight places amongst your live rock.

CaribSea Life Rock Shapes
CaribSea Life Rock

2) Crab

Emerald Crab

By Mark Loch - Female Mithraculus sculptus CrabUploaded by Betacommand, CC BY-SA 2.0,

Besides several species of hermit crabs, the Emerald Crab is probably the most reef-safe crab out there.  Emerald green in color and only reaching 2.5″ in length (6.4 cm), this small crustacean is known to eat bubble algae, as well as meaty prepared foods.  Nocturnal, once you put this crab in your tank it will be difficult to remove.

If the Emerald Crab does not have enough to eat, it will become an opportunistic feeder and turn toward corals and other invertebrates, so supplemental feeding may be required.

Scarlet/Blue Leg Hermit Crab

By Andreas März from Darmstadt, Germany - DSCN7340_16zu9Uploaded by Betacommand, CC BY 2.0,
By RevolverOcelot - Own work, CC BY-SA 3.0,

Some hermit crabs can grow quite large and be agressive, often eating your snails and small fish.  But both the Scarlet and Blue Leg Hermit are small in size and non-aggressive.

These omnivores will eat pretty much anything from hair algae and cyanobacteria, to fish food and waste.  Because of their small size, you need to keep quite a few in an aquarium to be effective members of the CUC.

One word of caution.  You need to provide a bunch of empty shells of various sizes for the hermits as they grow, or they will turn on your snails to steal their shells.

Chemiclean is an effective chemical solution to cyanobacteria

3) Shrimp

Scarlet Skunk & Blood Red Fire Cleaner Shrimp

By Хомелка - Own work, CC BY-SA 3.0,
By User:Haplochromis - Self-photographed, CC BY-SA 3.0,

Cleaner shrimp are an enjoyable addition to your aquarium.  Not only will they eat meaty foods, waste, and detritus, they are also known to clean parasites off your fish!  It is fun to watch a cleaner shrimp jump on the back of a fish and go to town.  Not all fish will tolerate this, so don’t be surprised if your fish aren’t huge fans!

Similar in nature, the only real difference between the Skunk And Fire Cleaner Shrimp is that the Scarlet Skunk plays nicer with members of its own species.  So if you are planning on housing several cleaner shrimp, you could go with one of each species, or a couple Scarlet Skunks.

Cleaner shrimp can live for several years in your aquarium, and will molt once a month or so as it grows.

I would start with one cleaner shrimp in a 20 gallon tank and go from there.

4) Conch

By H. Zell - Own work, CC BY-SA 3.0,

With beautiful shells and a lively personality, a conch is a great addition to your CUC.  Active omnivores, a conch will burrow through your sandbed helping to keep it aerated.  They will also eat algae and detritus on the surface of your substrate and lower parts of your live rock.

While not climbers, a conch can use its razor shaped leg to propel itself around your tank. They do feed for a good portion of the day, and may require supplemental feeding to stay healthy.

I would recommend adding one conch to a 20 gallon tank.

5) Starfish/Brittle Star

Sand Sifting Sea Star

By Nhobgood Nick Hobgood - Own work, CC BY-SA 3.0,

Many species of Starfish are difficult to keep in the home aquaria.  The Sand Sifting Sea Star is one of the easier species, as long as it’s well fed.

This Sea Star has a voracious appetite for all things detritus, and can run out of food quickly in a small aquarium.  I would only recommend this sand sifter if you have a well-established tank with a somewhat deep sandbed (2-3″ depth).

Beware, because this Sea Star can eat small inverts such as snails, so if it’s hungry you might end up losing other members of your CUC.

close up of white plastic bottle with purple cap and labeling. Picture of clownfish swimming in anemone with words "waste away" below.
Waste-Away helps break down detritus

Brittle Star

By © Hans Hillewaert, CC BY-SA 4.0,

Brittle Stars, while similar to starfish, use their long arms to move around an aquarium, whereas sea stars use tube feet to seemingly float around the tank.

Good detritivores, there are several species of Brittle Stars.  They are quite sensitive to changing water parameters, so I would only recommend these for larger tanks that have had several months to settle in.  

Brittle stars are mainly nocturnal, and they will climb around your live rock looking for pieces of uneaten food and waste.  Be sure to provide plenty of live rock, as the Brittle Star needs places to hide and rest during the day.

6) Urchins

Tuxedo Urchin

By Didier Descouens - Own work, CC BY-SA 4.0,

Red & Blue being the most common colors in Tuxedo Urchins, these voracious algae eaters can clean your live rock like no other.

In fact, sometimes they are too efficient and can starve to death.  They are also quite strong, so if your live rock is merely stacked on top of each other and not cemented together, you may wake up to a nasty surprise and find your aquascape destroyed.

Nocturnal, Tuxedo Urchins will graze your live rock for algae.  If necessary, be sure to supplement their feeding with seaweed.

I would say you need at least a 20 gallon tank that has plenty of live rock, but the bigger the better.  

7) Sea Slug/Cucumber

By I, Marrabbio2, CC BY-SA 3.0,

Don’t buy any of these.  Seriously, they may be beautiful but if and when they die, they emit a toxin that can kills every living thing in your tank.  So while they may be beautiful, they are not for a beginner.