If you are traveling a long distance or are so inclined to fit a cooler to exactly meet your needs, you can try this design, submitted by Joe Mark, a TIC teacher in Vermont. (PDF file)
NOTE: Whenever releasing fish into ANY body of water, you must have state approval to do so. If released into the wrong body of water, our small fingerlings can permanently alter an ecosystem. Please contact your coordinator for more information, or, if you do not have a state TIC coordinator, please contact your local state environmental, fishing, or wildlife agency.
TROUT RELEASE TECHNIQUES
Once you’ve arrived at the stream or second tank, it is important to slowly acclimate your fingerlings to their new environment. Monitoring the temperature of your cooler or bucket, slowly add water from their new stream or tank, one or two cupfuls at a time. The goal is to gently change the temperature of your cooler or bucket to near the temperature of the new water, allowing the temperature to change no more than a few degrees every ten minutes. Once the bucket/cooler temperature is within one or two degrees of the stream temperature, remove the fingerlings to their release container. To release the trout, lower their container into the stream and gently tip it to let them out.