What to Know About Otocinclus


In this Article

  • What Is the Otocinclus?
  • Otocinclus Fish in the Wild
  • Otocinclus Fish as Pets
  • Otocinclus Fish Are a Fascinating Species and Make Interesting Pets

Otocinclus fish are small catfish that are native to South America. Otocinclus fish are also called dwarf suckers or otos and mainly eat algae, making them a great addition to your home aquarium. 

What Is the Otocinclus?

Otocinclus actually refers to a group of 20 related species. Otocinclus fish are a type of catfish that are native to South America. 

What are catfish? Catfish are named for the long feelers on their face, which look like a cat’s whiskers. Some species have additional pairs of feelers, and some others have venomous spines on their fins. 

Catfish species vary widely. Most catfish live in freshwater, but some species live in the ocean. Some catfish, like the otocinclus, are very small, reaching a length of only an inch or two. Other species can reach up to 15 feet long. 

The otocinclus is most active at night. Like other catfish, otocinclus fish tend to be bottom dwellers and reside close to the bottom of the lake or river where they’re found. 

What do otocinclus fish look like? Otocinclus fish are some of the smallest species of catfish. The largest otocinclus size is typically a little longer than 2 inches. Female otocinclus tend to be larger than males. 

Otocinclus colors vary depending on the species. Some species are white with dark spots or a brown line that runs the length of their body. Other species are more colorful — the golden otocinclus, true to its name, is a golden yellow, while the zebra otocinclus is striped. 

Otocinclus fish are a type of armored catfish. Instead of scales, their bodies are covered with bony armor that helps protect them from predators and injuries. 

Are otocinclus used for food? Otocinclus fish are ornamental fish. Ornamental fish typically aren’t eaten but can be kept in aquariums as visually interesting pets.

Otocinclus Fish in the Wild

Where are otocinclus fish found? Otocinclus fish are distributed widely throughout South America. They typically live east of the Andes mountain range and can be found in Brazil, Paraguay, Bolivia, Venezuela, and Argentina. 

Otocinclus habitat. Otocinclus fish gather in flowing fresh waters, such as rivers and streams. They prefer to live near large aquatic plants and grassy shores. 

Running water is actually an important factor in the otocinclus breeding season. In the wild, these fish breed all year. However, they reproduce more frequently during periods when water levels in the river rise and the flow of the river speeds up.

Otocinclus Fish as Pets

Otocinclus fish are often kept as pets. These small fish are pleasant to look at, and their preference for eating algae makes them great tank cleaners. The otocinclus lifespan is typically around three to five years when kept as a pet.

Otocinclus diet. Otocinclus fish are herbivores, meaning that they only eat plants. They prefer to eat algae in the wild and will eat any algae that grows on their tank. 

If there is no algae in the tank, otocinclus fish can be fed algae wafers and green vegetables like zucchini, lettuce, and spinach. If you’re feeding your fish vegetables, make sure to finely chop the veggies before adding them to the tank.  

Otocinclus tank maintenance. Otocinclus fish should be kept in groups of five or more. They can live with other small fish, such as guppies or angelfish. However, since otocinclus are so small, avoid housing them with large or aggressive fish.

The tropical otocinclus fish prefers warm water and should be kept in water that is between 72 and 80 degrees Fahrenheit. The pH of the water should be kept neutral, between 6.8 and 7.5. 

Otocinclus fish are quick swimmers. When moving the fish to clean the tank, be aware that they may be difficult to catch.

Otocinclus health. Otocinclus fish are generally healthy but can be infected by parasites and fungi. Maintain a clean tank for your otocinclus and keep an eye out for signs of illness such as color changes, odd spots on their bodies, and reduced activity.

Otocinclus Fish Are a Fascinating Species and Make Interesting Pets

The tropical otocinclus are naturally found throughout South America. These small herbivores prefer to feed on algae and will help keep your fish tank clean. Otocinclus fish come in a variety of different colors and are a beautiful and helpful addition to any aquarium.

Show Sources

Brazilian Journal of Biology: “Reproductive ecology of Otocinclus vittatus (Regan, 1904) in the Pantanal floodplain, upper Paraguay River basin.”
FishBase: “Otocinclus affinis.” “The Beginner’s Guide to Otocinclus Fish.”
Proceedings of the Academy of Natural Sciences of Philadelphia: “The Neotropical Cascudinhos: Systematics and Biogeography of the Otocinclus Catfishes (Siluriformes: Loricariidae).”
Roger Williams University Feinstein School of Social and Natural Sciences: “Ornamental Fish.”

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