so far it has been ok alot of the species really don't spawn in large enough numbers to make the stunting going on.the koi i only have 6 of them in the pond they weigh from 6lbs to 14lbs i raised them up to about 2 lbs then i put them in the pond i had to get them big enough that the ospreys could not fly off with them and they have never got any offspring off i think everything eats there babies due to the brite colors. so far the blues and the flatheads have not had any offspring but could change.if i had to do it again i would probably not put crappie in there i usually take 100 to 200 out a year they really produce some offspring.it is a lot of work but i love to fish so it really isn't work. i have two different types of bullheads i have the brown and yellow bullhead.i enjoy catching both the brown seem to do a little better because they get bigger but i think the flatheads and bass keep them pretty well in check because there really isn't large numbers of them in the ponds.