Ive kept these a few times in the past but never more than a few months then id release them into my pond. Ive caught them up to 18-20" before and ive seen 17-19" as max size on multiple site but whats realistic in an aquarium? ive got a 65 to start and a 150 in storage for later. Fed good and clean water, whats the avg max size in captivity?
