Can you give me some more information on the bullheads, i though they got to 20inches.
It depends on where you look Karl
Some people with experience in say, for example Brown Bullheads that 10" is a common length in an aquarium, but 15" is possible. Other people say 17" or more (this is more indicative of a wild specimen IMO). If you watch some US fishing videos where they catch wild bullheads, you'll notice that for a Brown, a lot of the cats being pulled up are in the 12" range. If you look at State Records for the same fish, you find that 16" to 24" qualifies depending on the state. Mine are only 3" long right now so I can't really confirm or deny either side, but I'm going with the smaller size estimates based on my own experience with other fish captive vs wild size. I don't think every fish I keep is going to end up being a state record size-wise, lol.
Have not kept any other bullheads yet but Flat Bullheads (A. platycephalus) are one of the smaller members.