Choosing the Right Algae-Eating Fish for Your Aquarium

A nerite snail and cherry shrimp

For medium-sized tanks from 20-40 gallons, you have more options. Platies and mollies are lively, colorful small fish that constantly pick at hair algae, debris, and fallen food, and can be great choices for a medium community tank. A school of Otocinclus, stiphodon gobies, or panda garras can also be good choices, especially if you have a lot of surface algae.

For large tanks of 40 gallons or more, or to pair with larger fish, the Siamese algae eater is a classic choice. These fish are active, have personality, and are interesting to watch, and they generally get along with many other species of similar size. Rosy barbs are also an excellent choice for large tanks if you're looking for a more colorful schooling fish. Their hardiness, large size, and appetite for hair algae make them suitable for medium and semi-aggressive community tanks.

Rosy barb

There are many other great algae eater options out there; this is not an exhaustive list of species that can take on this role in your tank. Do some more research and visit your local fish store to see what they have in stock—you might be surprised by the variety!

If your local fish store lacks diversity or doesn't have the species you're interested in, you can check out these online retailers for more options.

Nutritional Needs of Algae Eaters

Algae eaters need more than just algae in their diet, and most require natural materials like real driftwood and/or plant matter such as Indian almond leaves to ensure they stay happy and healthy long-term. Algae eaters like snails and shrimp often need mineral supplements like Easy Shrimp and Snail Shells to support shell growth and molting. Small, sinking pellet foods like Magic Small Fish Feed are excellent choices to add important protein and vitamins to an algae eater's diet. You can also feed gel foods like Repashy or sinking wafers to ensure they get enough nutrients. Algae eaters are part of the community, and to make the most of their natural algae-eating behavior, a balanced diet for good health is essential.

Kuhli loach and Siamese algae eater enjoying a sinking wafer

Species Compatibility and Temperament

When adding new creatures to your aquarium, it's important to be aware of each fish's individual personality as well as the natural behavior of each species. If your betta fish has a habit of pecking at the eyestalks of ramshorn and bladder snails, then adding a nerite snail might not be a good idea, but a few large amano shrimp could be a reasonable compromise. If you keep larger cichlids, a Siamese algae eater might be the best choice, as smaller fish could become a snack. You can ask other aquarists in forums about compatibility experiences if you're unsure whether things will work out. It's always good to have a backup plan even if you're fairly confident a new member will integrate well, just in case.

Amano shrimp

Water Chemistry Compatibility

Like any new addition to your tank, water chemistry plays a role in determining how suitable that new creature is. Platies and mollies can be excellent algae eaters, but they require harder water and higher pH than some other species. Many snail species also often suffer from shell erosion in low pH environments, making them more suitable for tanks with a stable pH above 7.0. Otocinclus generally do not thrive in extremely high pH and prefer a pH range of 6.0-7.5. If your tank has very low or very high hardness and pH, you'll need to be more selective about which algae eater you choose.

Otocinclus

If you're unsure about your water chemistry, you can test it with strips like these to help decide which algae eater is suitable.

The Right Fish or Invertebrate for the Job

If you're a bit overwhelmed and still unsure which fish or invertebrate to choose for algae control, you can narrow it down by identifying the type of algae you want to control and which species does the best job. Fish with downward-facing mouths shaped like scrapers or suckers are more likely to eat algae and biofilm from surfaces. These fish can clean surface algae in your tank, and your glass will be very clean, but they may completely avoid filamentous algae and hair algae. Fish with more "nipping" mouths like platies, mollies, Florida flagfish, and Siamese algae eaters are more likely to eat filamentous algae types in addition to surface algae, especially after the algae starts dying off due to other control measures. By observing how these fish and invertebrates naturally feed, as well as their size, you can often make an educated guess about what type of algae they will consume and how quickly.

Aquarium overrun with hair algae

Part of the Ecosystem

Algae eaters can play an important role in maintaining the balance of our aquarium ecosystems by reducing unsightly algae between maintenance sessions. Besides being great little helpers, they are also very interesting to learn about and can easily become some of your favorite inhabitants in the aquarium.