Thats because almost all of gar man's threads are deleted by mods. However i personally dont believe that bullheads in gar man's area reached only 6 inch long, which its not genetically but more likely its enviroment. Once you give these bullhead properly husbandy, they will reach monster sized. All bullheads species and stonecat will reach more than a foot long, there are no such as dwarf bullheads in nature. And 40gal are terrible growout tank for bullheads, they grew up so quickly than other fishes which thats why channel catfish are commerical bred because of their fast growth rates, so are all bullheads which has this trait. 100gal are great growout tank for baby bullheads. I once caught two one inch long yellow bullhead a months ago and now they are 6 inch long and they are in 10gal tank!!! I gave the bullheads to good home. 100gal are not enough big for fullgrown bullhead (yellow, brown and black) so 125gal are permament home for these common species and NO TANKMATES!