Some fish like people and dogs just tend to be dumber or smarter. Are some breeds of dogs are generally smarter than others - companion or leader dogs? Ask a dog trainer about this trait. My cousin has a lab that is really really dumb, dumber than most I've seen.
Also involved is individuality, some more than others. This is genetic variation. It occurs in every species.
Also involved is I think some fish genetically tend to be more aggressive GSF vs yellow perch vs FHM. I don't consider a non-breeding RES aggressive at all - generally pretty docile compared to a GSF. If you put a similar sized BG and GSF together in a 20 gal aquarium without structure, 90%-98% of the time the GSF will nip, bump and chase the BG until the BG becomes fungused and dies or is very ill, usually in several days - usu less than 10 days. That was college research project for me as a senior "Agnostic Behavior of Two Species of Lepomis".
Last edited by Bill Cody; 02/23/09 10:46 PM.
