How many bristlenose plecos can you have in one tank?

The number of bristlenose plecos you can have in one tank depends on the tank size. A general guideline is to have one bristlenose pleco per 20 to 30 gallons of water, as they can grow to about 4 to 6 inches in length. However, if you have a larger tank, you might be able to keep a small group, ideally with a ratio of one male to several females to prevent aggression. Always ensure there’s enough hiding space and territory to minimize stress and territorial disputes.