"No" to Multiple Plecos Together
When plecos -- an abbreviation for plecostomus -- are in community aquariums, they can indeed thrive, but only if they are the sole representatives of their species. ... When plecos reach maturity, they simply cannot get along with fellow plecos.
How many plecos should be kept together?
Although Plecos can be housed with a wide variety of fish, they are very territorial towards their own species. As a result, it's best to be safe and only keep one Pleco per tank. Even with a large tank, it's important to avoid overcrowding your Pleco.
Do plecos do well alone?
Bristlenose plecos can absolutely live alone in a tank. They're perfectly happy by themselves and don't always need tank mates to keep them company.
