Algae-Eating Fish and Snails: Which Ones Should You Choose?
No species replaces regular maintenance, but certain fish and snails noticeably slow algae regrowth by grazing on what a scraper can't reach. This approach builds on a logic already well documented in aquaculture: in their reference work on herbivorous fish, researchers Opuszynski and Shireman showed how grazing species, such as grass carp, can effectively control aquatic vegetation at scale (study on Google Scholar). In the aquarium, the same principle plays out on a much smaller scale with far more discreet species. Our maintenance benchmarks are gathered in our fish care and grooming section.
Otocinclus and bristlenose plecos, the reference for glass and décor
The otocinclus, a small shoaling fish of 4 to 5 cm, scrapes brown and green algae off glass and broad leaves without ever touching plants; it does best in a group of at least six in an already mature tank. The bristlenose pleco is bulkier, reaching 12-15 cm, and works well on décor and driftwood, but needs a more generous volume and driftwood to gnaw on for its digestion.
Snails, a discreet complement
The nerite snail is the great algae-fighting ally of planted tanks: it can't reproduce in freshwater, so there's no risk of a population explosion, and it tirelessly cleans glass, décor and leaves. Ramshorn and pond snails, on the other hand, breed very quickly and are more something to watch than to introduce on purpose, as detailed in our guide to controlling pest snails in an aquarium.
Matching the choice to the algae type and tank size
Against hair and thread algae, Amano shrimp are often more effective than any fish. In a nano tank under 40 litres, favour nerites and small shrimp over a bristlenose pleco that will outgrow the space. None of these species fixes an underlying excess of light or nutrients: they complement maintenance, they don't replace it.
Frequently asked questions
Is one bristlenose pleco enough to clean a whole aquarium?
No, it reduces algae regrowth but doesn't replace scraping the glass or regular water changes.
Do nerite snails eat plants?
No, they feed on algae and biofilm on leaf surfaces without damaging healthy plants.
Can you combine several algae eaters in the same tank?
Yes, as long as the volume supports it: otocinclus, nerites and shrimp coexist very well. Find all our guides on the aquarium hub.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.