Aquarium Clean Up Crew

We hobbyists take pride in maintaining healthy environments for our pets. We struggle day-by-day to keep their homes pristine and ideally suited to their needs, but there’s always the threat of disaster looming on the horizon: algae, ammonia spikes, too many nitrates! Luckily we can enlist the help of certain organisms to keep the dangers at bay. I call them…. The Clean Up Crew!

Beneficial Bacteria

Beneficial Bacteria (BB) are the first and greatest allies to us hardworking fishkeepers. They come in stages, beginning with Nitrosomonas and then Nitrobacter. These microscopic organisms are your first line of defense against your water becoming toxic to your fish and invertebrates. They turn your pets’ waste into progressively less toxic substances, until they can either be consumed by plants or washed away with your next water change. Their critical role in aquarium filtration cannot be overstated. If you aren’t familiar with what exactly these bacteria do, check out my article on The Nitrogen Cycle.


There are many kinds of worms that can be found in an aquarium. Some are beneficial, while others have a sinister reputation (planaria are thought to be harmful to shrimp). There are, however, plenty of worms that you would benefit from having in your tank. Blackworms, dero worms, and other detritivore worms are great to have sifting through your substrate. They live by eating decaying matter and the waste produced by other animals. Not only that, many fish and invertebrates naturally feed on these worms. So a healthy colony of this slimy wigglers can provide your fish an exciting and nutritious supplement to their diet.

While it is good to have some of these worms in your aquarium for keeping things tidy, you should be concerned if there is an overwhelming number of them. The worm population in your tank can be a helpful indicator of the overall health of your aquatic system. A sudden boom in their population could indicate that your tank isn’t as clean as you thought. These types of animals reproduce proportionally to how much food is available. If you notice a sudden explosion in their number, it could mean that you have a build up of decaying material somewhere in your tank.

As with the other animals on this list, worms will contribute to your overall bioload. If something triggers a large population of worms to die at once, this can cause an ammonia spike. So it is always good to try and make sure their numbers remain under control.


Depending on who you talk to, snails are either a delightful inhabitant of an aquarium or an unstoppable pest. I personally consider them to be an ally to the aquarist. Snails, like worms, will happily consume various waste materials that tend to collect in the dark and slow corners of our aquariums. They are constantly feeding as they glide around the tank. Many species of snail will happily graze on algae as they travel, helping to keep your tank walls clean and clear. All of these snails have slightly different preferences for food, and it’s good to have a mix of these to tackle different forms of algae in your tank.

There are many species of snail that are available as decorative pets as well as many species that seem to find their own way around. Some collectible snails include the colorful nerite, apple, rabbit, and mystery snails. These snails tend to be a bit larger, with nerites as the smallest. Hobbyists collect these species for their size, shell colors, and relative ease of care compared to pets like shrimp or fish. Other snails, like ramshorns, bladder, and trumpet snails tend to find their own way into our tanks. They do so often by hitching rides on plants and in substrate from one tank to another.

Not everyone appreciates seeing many snails crawling around in their aquariums. Like worms, if you see a sudden burst in their population, it could mean you are overfeeding, or there is something amiss in your tank. If you would like to rid yourselves of these shelled guests, take a look at my article on pest snails.

Freshwater Crustaceans

Amphipods and Isopods

Amphipods (aka scuds) are one of my favorite mini clean up crew members. They are much maligned in the freshwater aquarium community, because of their talent for eating some plants. In my experience, they do nibble on plants like java moss and those with soft leaves like staurogyne repens. So if you are keeping live plants in your aquarium, it’s best to do a bit of research first, before introducing amphipods to your aquarium.

Scuds have a few ways of benefiting an aquarium habitat. Their small size and tendency to swim through the open water make them an ideal live food for predatory species like betta fish. My dario dario (scarlet badis) happily feed on tiny, juvenile amphipods. They also spend much of their time digging in the substrate, where bottom dwellers like catfish will happily slurp them up.

Because scuds spend much of their time burrowing into the substrate, they provide the valuable service of aerating the substrate. This can help prevent certain harmful anaerobic bacteria from producing dangerous gas. Lastly, scuds are constantly grazing and nibbling, which helps to reduce the buildup of excess food or waste in the substrate.

Isopods fill a very similar niche as amphipods. They are closely related to pill bugs that can be found underneath rocks and logs on land. Like amphipods, they root around in the substrate and under larger objects, looking for an easy meal. Again, like amphipods, they can be a source of live food for fish and other aquatic pets.


Shrimp are the jewels of the aquatic freshwater invertebrates. Unlike scuds and isopods, they come in a variety of colors, patterns, and sizes. Hobbyists around the world breed and trade decorative shrimp and participate in juried shows and conventions. Not only are these shrimp fun to look at, they can help us to maintain clean aquarium habitats for our other pets. Shrimp are primarily algae and biofilm eaters, which makes them adept at cleaning plants and decorations from unsightly patches of green or brown algaes. Amano Shrimp particularly are known for chowing down on algae.

Plants & Algae

Living plants are a tremendous benefit to an aquarium. They produce oxygen as a product of photosynthesis, absorb excess nutrients from the water, and constantly shedding organic material that many species consume as food. Some fish utilize plants as a staple in their diet, while others use them as brooding locations. Duckweed, for example, is a terrific supplemental food source for fish such as goldfish.

“What? Algae? I thought you said we were trying to avoid algae!” Think of algae, like most things in life, as being “good in moderation.” A little algae can do a lot of good in your aquarium. A lot of algae can cause big problems.

Like plants, green algae produces oxygen as a byproduct of photosynthesis. If you’ve ever seen a Marimo Moss Ball producing bubbles on its surface, then you’ve witnessed algae producing oxygen. Also like plants, algae soaks up nutrients from the water in order to grow properly. This process helps to clean the water by removing those substances from it. Too much algae can be problematic, by competing with plants and by producing an ammonia spike, if a big bloom of algae were to die at once.

Kept healthy and under control, plants and algae are (after beneficial bacteria) the best allies to have in your aquarium. In addition to producing oxygen and soaking up nutrients, plants and algae will also reduce your overall bioload. They not only do this by not producing ammonia waste, they actually consume Nitrates to aid in their growth.

Research Sources

Central Florida Aquarium Society

“Ecology of the Planted Aquarium” written by Diana Walstad

“Encyclopedia of Aquarium Plants” by Peter Hiscock

“An Alternative Aquarium: A Robust Habitat” by Matt Owens

Cherry Shrimp –

Feature Image Credits: (from left to right) Buchling, DirkBlankenhaus, Alan R Walker, Dvortygirl Michael Maňas. Source:

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