Netting him usually is enough to get him to release. I would set up a fry tank immeadiately and then net him, expecting him to release the fry during the transfer. If that doesn't work, let him sit in the fry tank until he releases or chase him around the tank with a net. There are other ways to get them to release, but these methods have worked for me in the past and are not as stressful as the others.