Yeah, releasing fish into the wild is dumb and it appears its mainly fish who outgrow their owners tanks but on the other what can you expect from somone who didn't even bother to research their fish's max size in the first place? Not that thats any consolation anyway...
When i used to live in Australia, i was visiting friend who lived right next door to the towns park which happened to have a lake in the middle of it. We were taking her dogs for a walk around the lake one day when i saw somthing huge and orange lurking in the shallows... as it came closer we realised it was this HUGE moster sized koi karp, no kidding it was 3ft long!!! Over the next week we counted 4 of them, 3 being 3ft+ long and one 2ft long white one- we considered catching them but it would've looked quite dodgey doing that in the towns lake in its park.