Originally posted by lv4dogs

AND I also know of a lot of plecos that are very very old & are not that big. I've heard that plecos can be kind of like gold fish that they will grow to their size of tank. I'm not sure how true it is but I have witnessed it so I believe it, to a degree anyways. The plecos I have seen did stop growing and do still fit in the tank easily & comfortably but I think they would be even more comfortable in a bigger tank, but I also believe that for any fish or animal. Get them the biggest environment possible.
Plecos, like gold fish, will grow to the size of their tank, but it is unhealthy. Although their body stops growing, their internal organs don't. Most of the time plecos (and goldfish) in that situation don't live as long as they should.