10 Favorite Cleanup Crew Members for a Saltwater Aquarium

What It Cleans

Scarlet Reef Hermit Crabs are useful general-purpose scavengers. They pick at several types of algae, search the rockwork for uneaten food, and help consume organic material before it has a chance to break down.

Why It Made the List

There are plenty of hermit crabs available to reef keepers, but Scarlet Reef Hermits tend to be less aggressive toward snails than some larger or more territorial varieties. They also reach a useful size without becoming as intimidating as larger hermits with oversized claws.

What To Know Before Adding One

No hermit crab is completely harmless. A hungry hermit may attack a snail for food or take its shell, so provide several empty shells in appropriate sizes and make sure there is enough food available. Avoid adding more hermits than the aquarium can support.

What It Cleans

Trochus Snails are active algae grazers that spend much of their time cleaning the rocks and aquarium glass. They're especially useful for controlling film algae and short growth before it becomes more established.

Why It Made the List

Trochus snails are dependable little lawnmowers, but one of their best features is their ability to right themselves after falling over. Snails that can't flip themselves upright may need regular help and can die if they remain upside down for too long.

Trochus snails can also reproduce in established reef aquariums. This doesn't happen in every system, but a healthy group may gradually produce a self-sustaining population.

What To Know Before Adding One

Trochus snails may occasionally climb close to the rim of an uncovered aquarium. They also need enough algae to graze, so avoid adding a large group to a brand-new or extremely clean system.

What It Cleans

Tuxedo Urchins are powerful grazers that can mow down hair algae and other growth from the rockwork. They're often more effective than smaller snails when algae has become thick or established.

Why It Made the List

Along with being excellent cleaners, tuxedo urchins are entertaining aquarium animals. They often decorate themselves by carrying loose shells, algae, rubble, and other small objects on their backs. They're also available in several attractive color variations, including blue and red.

What To Know Before Adding One

Anything loose in the aquarium may become an urchin accessory. Frag plugs, small rocks, and unsecured corals can be picked up or pushed over. Glue corals securely to the rockwork.

Tuxedo urchins remain a more manageable size than many other types of urchins, but they still need an established aquarium with enough algae to support them.

What It Cleans

Sand-sifting sea cucumbers slowly move across the bottom of the aquarium, taking in sand and processing the edible organic material it contains. Their movement helps turn the substrate and reduces the chance of debris collecting in stagnant areas.

Why It Made the List

Sea cucumbers aren't always the fastest or most efficient cleaners, but they are fascinating to watch. Many become more active after the lights go out and use unusual feeding structures around their mouths to collect food from the sand.

What To Know Before Adding One

A sand-sifting cucumber needs a mature aquarium with a large enough sandbed to provide a steady food supply. It shouldn't be one of the first animals added to a new system because a clean, sterile sandbed almost never contains enough food.

Most cucumbers are better suited to mature aquariums around 75 gallons or larger. Research the exact species before purchasing because care requirements and adult sizes can vary.

What It Cleans

Fighting conchs search the surface of the sandbed for algae, detritus, and uneaten food. Their long, flexible mouth allows them to vacuum up material while their movement helps disturb the upper layer of sand.

Why It Made the List

A fighting conch is a lot like a tiny robotic vacuum for the sandbed. It cruises along the bottom of the aquarium, cleans the lower portions of the glass, and can move a surprising amount of sand for a snail.

Despite the name, fighting conchs are generally peaceful. They use a strong, blade-like operculum to push themselves forward or launch themselves across the substrate, which can look dramatic but is normal behavior.

What To Know Before Adding One

Choose a true fighting conch or another known reef-safe species. Some larger conchs have very different diets and may not be suitable for a reef aquarium. Fighting conchs also need open sandbed space and enough natural food to support their grazing.

What It Cleans

Sea hares are specialized algae grazers that can consume an impressive amount of hair algae. In the right aquarium, they may clear areas that snails, hermit crabs, and many algae-eating fish ignore.

Why It Made the List

Sea hares are unusual, active, and extremely effective when there is plenty of algae available. Some smaller varieties have attractive turquoise or blue spots and remain much more manageable than the large brown or green sea hares commonly seen in stores.

What To Know Before Adding One

Sea hares are easy to starve once the algae is gone. Large common varieties are best reserved for big aquariums with a serious hair algae problem. Some aquarium stores offer sea hare rental or return programs because the animal may run out of food after clearing the tank.

Smaller blue-spotted varieties may be more suitable for an established aquarium around 80 to 120 gallons or larger, but they still need a dependable supply of algae. Sea hares should be added to solve an existing food-rich situation, not as a precaution against algae that may appear later.

What It Cleans

Nassarius snails are scavengers rather than traditional algae grazers. They burrow beneath the sand and quickly emerge when they detect meaty food, leftover fish food, or other organic material.

Why It Made the List

Watching a group of Nassarius snails rise out of the sand at feeding time is one of the most entertaining cleanup crew behaviors. Their sudden appearance has earned them nicknames like zombie snails.

They're also excellent at finding food that lands in the sandbed before it has time to decay. Because they spend much of the day buried, they are less exposed to fish that may pick at other snails.

What To Know Before Adding One

These snails do not replace algae grazers because algae is not their main food source. They are best used alongside Trochus snails, urchins, or other animals that clean the rocks and glass.

What It Cleans

Stomatella snails graze algae from the rockwork, glass, and small spaces that bulkier snails can't easily reach. Their streamlined bodies make them especially good at moving through narrow cracks and uneven reef structures.

Why It Made the List

A Stomatella looks a little like a slug carrying a tiny fingernail-shaped shell on its back. They come in several colors, including tan, brown, black, purple, and bluish shades.

They are reef safe, reproduce readily in established aquariums, and often create a sustainable population without any special effort.

What To Know Before Adding One

Stomatella snails aren't always easy to find for sale. They commonly enter aquariums as hitchhikers on live rock, coral frags, or equipment from established systems.

They are usually most active at night and quickly retreat from bright light.

What It Cleans

Reef-safe limpets graze algae from the aquarium glass and rockwork. Their flat bodies and cone-shaped shells allow them to move through tight spaces and underneath ledges where larger snails may not fit.

Why It Made the List

Limpets are hardy, effective, and capable of reproducing in established aquariums. Many reef keepers receive them as hitchhikers rather than purchasing them intentionally.

They attach to hard surfaces with an extremely strong grip. This helps protect them from predators and allows them to remain firmly in place when water movement is strong.

What To Know Before Adding One

Not every limpet is appropriate for a reef tank, so identification matters. Some species may graze coral tissue instead of algae.

Avoid pulling a firmly attached limpet directly from the glass because forcing it loose may injure the animal. If one needs to be moved, gently work at the edge of its foot rather than pulling on the shell.

What They Clean

Depending on the species, algae-eating fish may graze film algae, hair algae, Bryopsis, bubble algae, and other growth from the aquarium rockwork. They provide movement and personality while performing a useful job.

Why They Made the List

When we think of a cleanup crew, we usually think of shrimp, snails, hermits, and other invertebrates. But fish can be great cleanup crew members too! Fish such as tangs, rabbitfish, foxfaces, and algae-eating blennies can be an important part of algae management.

Rabbitfish and foxfaces are particularly useful in larger aquariums because many individuals will sample stubborn algae that well-fed tangs may ignore. Tangs often become selective when they receive plenty of prepared food and nori.

What To Know Before Adding One

Choose a fish based on the aquarium's size, compatibility, and the algae you want it to eat. Large tangs, foxfaces, and rabbitfish need plenty of swimming space and shouldn't be added to small aquariums.

For nano aquariums around 15 gallons or larger, a Tailspot Blenny may be a better option. It stays small, has plenty of personality, and spends much of the day picking at algae on the rockwork. No fish is guaranteed to eat a specific nuisance algae, so individual behavior should always be considered.