I don't know about pitbulls, but I have BN's in with goldfish, and of the two, the BNs are more destructive to the plants, just because they tear through and uproot stuff. I wouldn't expect a perfectly planted aquarium with any pleco.
some of the bigger ones will also munch plants. not because they are trying to eat your plants though. they want the bio film that develops on the leaves, but are so big and powerful that they end up destroying the leaves :/
my gibby and the L239's i had all destroyed plants.
ah, I guess its a hit and miss then. I knew that large plecos uproot plants but was hoping smaller ones wouldn't hurt them at all. I've heard that if you feed them veggies often they're less likely to mess with the plants, is this true?
I have never had an ancistrus species that harmed plants. The worst IME is they can bury some shorter plants in sand as they kick it up but no physical damage.
i have a BN (about 3 or 4 inches) in my planted tank and have never had any issue with plants being uprooted or holes in the leaves from him rasping on them.
I have had several different bn plecos (long fin browns, long fin albinos, and long fin blue eyed albinos right now) in my heavily planted tank and never seen an issue with the plants..