It all depends on the species and their water temperature preference. Our typical fish, bass, catfish, crappie, bluegill grow in warmer water and not so much, if any, in the winter. Walleye can probably grow well in the cooler months and not so much in the hottest part of the year. There has been some research to indicate that crappie don't do as well when the water temp is in the 80's. In general our growing season is the 8-9 warmest months. Unless it's trout, then cold is better.