Clean-up crews play an essential role in a marine aquarium, doing as their name suggests by helping to remove unwanted algae, leftover food and other waste.
What is a Clean-up Crew & Why is it Important?
The clean-up crew is a group of invertebrates whose primary purpose is to help clean and maintain an aquarium. The most common members of a clean-up crew include snails, crabs and starfish. Clean-up crew members remove detritus, leftover food and other waste, preventing them from building up over time. They also play an essential role in keeping the sand bed clean and healthy. While not a substitute for regular tank maintenance, a clean-up crew is always working and can reach spots in your tank that your cleaning cannot.
When to Add Clean-up Crews
We recommend adding clean-up crews after the tank is completely cycled and after the appearance of algae. Adding them before the tank has finished cycling can expose the clean-up crew to deadly ammonia or nitrite. Adding them before algae (a primary food source for many clean-up crew members) is present can lead to starvation.
In the reef hobby, there are many options for clean-up crews and it is vital to consider the upsides and downsides of each. The size and bio-load of the tank, the style of aquascaping as well as the type of sand bed (or lack of a sand bed) all impact what kind and how many clean-up crew members you’ll need. Some of the most popular clean-up crew members in the hobby include:
Nassarius Snails: A sand-sifting, medium-sized snail with a larger-than-life appetite, these snails are known for continuously turning and cleaning the sand bed.
Fighting Conch: A sand-sifting, larger-sized snail. Like the Nassarius, these snails continuously turn and clean the sand bed.
Turban Snail: A small to medium-sized snail known for eating some of the most frustrating tank elements in the hobby, including diatoms, film algae, and Cyanobacteria.
Cerith Snail: A small to medium-sized snail known for eating diatoms, film algae, and Cyanobacteria.
Mexican & Zebra Turbo Snails: Medium to large-sized snail known for their ferocious appetite for algae.
Nerite & Banded Trochus: Small to medium-sized snail also known for their ferocious appetite for algae.
Red Leg and Dwarf Zebra Hermit Crab: They are reef-safe and will eat algae, detritus, and other waste. They remain relatively small in size, making them one of the most favored hermit crabs.
Blue Leg Hermit Crab: Larger than the red leg and dwarf zebra crabs with a bigger appetite. The blue-legged hermit crab is known to feast on cyanobacteria, green hair algae, and much more. Their larger size can knock over tank decor, and they are known for killing snails for their shells, so providing them with empty shells is a good idea.
Emerald Crabs: Omnivore who is known for eating bubble algae, emerald crabs will also eat leftover food, decaying matter, fish waste, other algae, and more.
Sally Lightfoot: Brightly colored scavengers known for eating algae, leftover food, and dead tank members and rumored to catch and eat small fish when not adequately fed.
Coral Banded Shrimp: A known asset if you’re trying to cure a bristle worm problem, this shrimp is also an excellent asset for decaying matter like food or dead livestock that gets trapped in the impossible to reach places of a reef. Can be aggressive towards other shrimp.
Peppermint Shrimp: One of the few inverts known to eat the dreaded hitchhiker anemone, the Apitasia, this shrimp is a carnivore as well and a great scavenger. Some have reported it not to be reef safe, but in most situations, it is a case of mistaken identity with its look-alike, the camel shrimp, which is not reef safe.
Brittle and Serpent Stars
Brittle Star: Reef-safe invertebrate covered with lots of spines and spikes of various sorts and sizes. They are considered scavengers that feed on detritus, decaying food, dead organisms, and other organic matter among the rock and sand. Tolerant of a wide range of water conditions.
Serpent Stars: A closely related relative to brittle stars, the serpent star is smooth in appearance. Serpent stars are also scavengers that feed on detritus, decaying food, dead organisms, and other organic matter among the rock and sand. Also, reef-safe and tolerant of a wide range of water conditions.
Tang: A commonly available fish, most tangs are great at algae control, and except for a few, most are reef safe as long as you have a large enough tank to suit their needs. Popular species of tangs include Yellow, Gem, Kole, and Powder Blue.
Blenny: An algae-eating fish with a big personality. Most blennies are relatively easy to care for and are reef-safe. Popular species of blennies include Lawnmower and Starry Night.
Copepods and Rotifers:
These tiny organisms fit into the smallest places in live rock and feed on detritus, decaying food, silica, phosphates, nitrates, ammonia and other organic matter. Copepods and Rotifers are also a food source for many coral and fish.
What to Buy
As a general rule of thumb, use one clean-up crew member for every 3 gallons of water in a new tank and two clean-up crew members for every 3 gallons of water in an established tank. However, stocking levels can vary depending on the tank’s footprint and the tank inhabitants and bioload. Here’s what the clean-up crew in a typical 100-gallon tank might look like:
New 100-gallon Tank:
- 10x Nassarius Snails
- 5x Astraea Snails
- 10x Red Leg Hermit Crabs or Dwarf Zebra Hermit Crabs
- 5x Blue Leg Hermit Crabs
- 1x Brittle or Serpent Starfish
Established 100-gallon Tank:
- 20 Nassarius Snails
- 10 Astraea Snails
- 20 Red Leg Hermit Crabs or Dwarf Zebra Hermit Crabs
- 10 Blue Leg Hermit Crabs
- 1 Brittle or Serpent Starfish
Species to Avoid
Sand Sifting Starfish: Reef safe and readily available, and excellent at cleaning the sand bed; however, they are sensitive to changes in the oxygen levels, salinity, and the pH of the water. They also do their job too well and feed on everything, including the beneficial bacteria living in the sand bed. In most tanks, they will deplete the sandbed of any food source and die off and begin to decay.
Margarita Snail: Commonly sold in the hobby; however, they are cold-water snail that will generally slowly die off in the warmer waters of a reef tank.
Bumble Bee Snails: Known to feed on other snails.
Sea Cucumber: They are challenging to keep, and they can be poisonous, threatening everything in the tank.
Nudibranch: Beautiful and fascinating creatures; however, nudibranch diets are very particular. For example, the Lettuce Nudibranch only eats hair algae, and the Berghia Nudibranch only eats Apitasia. After they run out of food, they will die of starvation.
It is common for members of clean-up crews to die over time. Unless a significant number of them die off within a short period, it is generally not a big deal. With that said, it is vital to replace or replenish lost clean-up crew members regularly.
Have a question or recommendation regarding clean-up crews? Feel free to drop us a line here. If you are in the need for saltwater aquarium supplies, Simplicity Aquatics offers a variety of products including protein skimmers, pumps, dosing containers and filter media.