Yes a chiller is a must, during college on a local electro fishing trip we caught a 8" one that we kept for the semmester. We originally placed him in our indoor tanks with the other natives but soon realized something was wrong(the water was too warm) so we moved him down to the hatchery. Placing him in one of the empty fry tanks which was a flow through system from one of our two wells. He did much better in there growing at a fast rate also, at the end of it we released him back into Onieda lake at close to 20".