Two plecos can live together at the most. Their size and aggressive, territorial behaviors make keeping two plecos together a difficult situation.
Even though plecos are usually peaceful, they’re typically territorial and aggressive towards other plecos. It can be dangerous to house multiple plecos together, as they can fight and injure each other.
With that said, plecos are generally friendly and good-natured when it comes to other fish. You should try to house one pleco in a community tank with other species. Some excellent tankmates for plecos include:
However, you can keep two plecos together for a brief time when you want to breed them. After breeding, you should separate them immediately. Even then, they will need a large, 120-gallon tank or bigger.