Please elaborate. There are springfed lakes that I love to fish in central florida that have 3 different types of catfish, shiners, LMB, SMB, pickerel, gar, crappie, and 4 different types of sunfish/bluegill as well as carp (pretty sure grass carp).
The only nuisance fish in that ecosystem is the tilapia. Because they are known to attack but not eat the other fish's nests, and they are mouth brooders. Meaning that they harbor their young themselves in their mouth to give their species a winning edge as they drive out the competition by breeding them out.
Correction to this- carp are also a nuisance fish and an invasive species.
And if you want to get technical, lmb are also an invasive species that does not originate in america. Im pretty sure that goes for smallmouth too.
Sent from my SAMSUNG-SGH-I747 using MonsterAquariaNetwork App