Hey Dan, how's Big Red?
I've done it for short hauls without aeration and had no ill results. Larger fish generally don't do as well. Water temps certainly make a difference. I've added a couple of drops of clove oil, thanks to Todd Overton, and it somewhat sedates them. That certainly seems to make a difference.
Small aerators a inexpensive but, without crowding, you may not need it.
I agree with Dave - transferring smaller less crowded fish in cooler weather is not a problem.
For larger fish, a few drops of clove oil in an appropriate size Igloo cooler with O2 system shown in photo below, will safely transport larger species of fish.
An O2 system is inexpensive and easy to rig up - I find it indispensable for routine fishing in hot weather conditions as well as transporting fish.
Excellent system for resuscitating stressed fish.
George
