Otocinclus: Algae-eating Catfish for Your Aquarium
Otocinclus (auto-sink-lus) are algae eating catfish from the family Loricariidae. Most of the species top out at around 2 inches. Otocinclus are schooling fish so they should be kept in groups of at the very least 3. Different species of otos don't school so make sure you select otos that are the same species. Most otos available are wild caught so they are in very bad shape when you get them. Make sure they have plenty of food otherwise they will quickly waste away. Otos enjoy eating soft green algae on plants and decorations in the tank but have trouble eating the algae on the glass of your tank. If there is no algae in your tank, you need to feed them otos veggies such as summer squash, romane lettuce, kale, spinach, beas, broccoli and fruits such as apple and pear, etc. Some of these vegetables and fruits need to be blanched before they are put in the tank. Algae wafers are no good for otos bbecause most hold little vegetable matter. Otos breeding in aquariums are uncommon. As long otos are happy and healthy they are hardy fish that can live 5 years.
Otocinclus feed mainly on algae, and the best tank has a lush growth of algae for them to feed on. Driftwood tends to support a healthy growth of algae for them to browse on. It is hard for them to navigate the algae all the way down on a rough surface like wood, it's likely that there will always be something to eat on a piece of driftwood.
Aquariums often do not support enough algal growth to feed a school of these fish so you may need to supplement their diet with blanched spinach or zuchinni. Food that has been dipped in boiling water or microwaved for a minute is more attractive to Otos. An algae clip or a rock can be used to hold the material in place.