Yes, otos are schooling fish. Otos are very social, and living in schools makes them feel safe and comfortable. A small group of five to six otos is a great starting point for most fishkeepers.
In fact, wild otos usually live in schools that have thousands of fish. When otos are separated from their school, they get stressed quickly.
Keeping otos in a group helps them stay happy and comfortable. If you have the space and the resources, aim to keep 10-20 otos in your tank. Just make sure to provide enough space for your otos to swim around!
An inch of fish requires at least one gallon of swimming space. Otos are generally two inches, so each fish needs around two gallons of space. So, for a small school of five to six otos, you’d need a 10-gallon tank.