Algae eating fish are a must have on a fresh water aquarium as they provide the very necessary biological algae control. If you don’t want your tank to become green and dirty and your fishes to suffer, a good mix of algae eaters will keep most algae presence under control. Unless you have a severe water imbalance, algae eating fish will most likely need some commercial food to keep them happy after they have eaten the problematic algae from your tank, and besides being useful they will add visual appeal to the lower levels of the tank.
Depending on your tank setup and existing inhabitants some algae eaters may not be recommended. It is important to always keep compatibility with existing fish at the top of your mind, before introducing a particular algae eating fish species that could harm the balance of your tank. Since most algae eaters are pretty pacific, you may find that aquariums with very lively or aggressive species can’t accommodate smaller individuals likely to be eaten. We have tried to list any potential issues but it’s worth reading a more in-depth article about your chosen algae eater species before committing.
Algae eaters can be divided into algae eating fish and algae eating invertebrates.
Top Algae Eating Fish
Leopard Sailfin Catfish / Clown Plec
Plecos or catfish, as they are also known, are one of the most hardy algae eaters and that makes them an incredibly popular fish among aquarists. They are easy to recognize thanks to their underslung suckermouth and tall dorsal fin, along with a half-moon shaped tail fin. This fish gets very large as an adult, measuring over 30cm (12″) and living for 10 or 15 years in captivity. Most species have dark leopard-like patterns that makes them look dark brown, but you can find albino plecos as well.
Catfish are a great freshwater fish for beginners, as besides eating algae and other refuse they are hardy and pacific, at least while they are young. Their body is covered with bony plates (armor clad scales) and you will often seen him using its suction-cup shaped mouth to adhere to the aquarium walls, sucking up algae of all sorts. As they are pretty large fish they can deal with a lively aquarium including Cichlids, however they have been known to remove the slime from fish like Disqus and Angelfish. Also, as they grow older they may become more territorial and aggressive, and may eventually require their own tank.
Siamese Algae Eater
Crossocheilus oblongus; syn. Crossocheilus siamensis
The Siamese Algae Eater is a freshwater fish on the carp family, that originates from mainland southeast Asia. Several similar species are sold in the aquarium trade as Siamese Algae Eater, particularly the red algae eater which is the perfect algae eating fish if you don’t like the look of Catfish.
They are hardy fish that swim fast around the aquarium and will school together if kept in a group. They can be kept in community tanks as most exemplars are not agressive, and are incredibly effective to clean up heavily planted tanks with heavy lighting that are prone to algae. They will eat fish food if no algae is available, so they are pretty trouble-free. One to five individuals in a large tank is a good number to keep.
The main issue with Siamese Algae Eaters is the fact that they require a pH that is stable at 7, and plenty of oxygen and moving water. They are lively and curious fish that need to explore and will jump out of an open tank. They can reach up to 14cm long.
This delicate algae eating catfish can reach 10 to 20cm long, with a sucker mouth and a slender body that has a beautiful brownish color. It is an avid eater of most common algae species and appreciates a spiruline algae treat every few days. They thrive in environments with a lot of plants and bogwood, and given their size you will need a relatively large aquarium. They are very sensitive to brusque changes on water conditions, so if you want your whiptail catfish to be happy you should aim for small water changes every week, instead of larger ones less often. An aged aquarium that has been fully cycled and is stable is best.
Avoid keeping Twig catfishes with Cichlids and Barbs, as they could be killed or injured. Pacific community aquariums create the best environment for this fuss-free algae eater fish. It requires crystal clear water and tends to be shy, so an aquarium with small fish suit better. Good tankmates are danios and other Loricariids.
Top Algae Eating Invertebrates
Provided you don’t have Loaches or use tank fertilisers or medication that contain copper, invertebrates are a fun addition to any tank and will happily get rid of problem algae. Invertebrate algae eaters include snails and crustaceans such as shrimps and crabs.
Malaysian Trumpet Snail
This algae eating snail is a favourite in the aquarium trade for a variety of reasons. To start with, they are pretty small (never reach over 2cm when fully grown) and will eat algae and organic refuse, without harming your beloved aquarium plants. They are mostly subterranean and only go up to the surface at night, so you may not be seeing much of them. However, they will dig around the substrate reducing the chance for anaerobic pockets to form in fine substrates such as sand.
If you want to keep this kind of snail, snail eating fish such as loaches and gouramis need to be avoided as they will suck them right out of their shells. This kind of snail requires slightly alkaline, mineral heavy water and are very sensitive to dirty and contaminated water so frequent water changes are a must.
A superb algae eater, amano shrimps have been a popular option in the aquarist trade for decades. They don’t really breed in freshwater, and enjoy planted aquariums where they can hide from larger fish that would prey on them. Very pacific, they reach about 3.5 to 5cm, and their translucent bodies are beautiful to look at. They will not only eat algae, but organic detritus and leftover food, particularly if you don’t feed them too much.
Plant fertilisers contain copper, which can hurt them. It is important to make frequent water changes to dilute the toxicity of the fertiliser. They are group animals, so three or more per tank will be the happiest.
Using biological means to control algae by selecting algae eating fish and invertebrates is not only the cheapest option, but also the easiest way to keep your aquarium’s balance without resorting to chemicals and possibly damaging the water quality. Algae eaters are both useful and fun to watch, and will keep your tank clean without any effort on your side.