I have a 120l tank with freshwater tropical fish, which I inherited from work when they got rid of their aquarium - so I'm fairly new to fish keeping and no expert! Until recently I had two what I think are bristle nose plecos, which had lived together for a long time. A month or so ago I added a common pleco (I think!). After a bit of initial tussling, they seemed to have settled down together. Today I noticed an centimetre long pleco baby in the tank! Is it more likely that the two bristle noses have bred, or could the common have bred with one of the bristles? If I need to evict a fish to stop further breeding, which is the likely culprit for daddy?! Any advice is greatly appreciated, thanks!