Do snails impact oyur bioload?

Yea, I had a bi color dottyback in my tank and it terrorized EVERYTHING!! I thought it was working out at first, but once the 3rd day or so hit it thought the whole tank was HIS regardless of him being the last added! That was in a 20gal though, but from what I saw even in a 125 he may become a problem. He may claim a whole up to half of a 125 to himself and chase, nip and attack any other fish in there that goes into "his half". I dunno... just from what I saw when I had one, he may be too big of a problem whether it be sooner or later I actually brought back my dottyback to the LFS I got him from and there was a woman there looking to add a dottyback to her 30gal and I was able to convince her to go for something else. I have 4 letters that describes the dottyback.... E.V.I.L!!!! LOL