Yeah, that's something a kid would do on impulse. Even if it's not harming anything or he would have ended up in pan, then so be it. That's one less fish to spawn there and keep the ecosystem going. It's always best to leave things where they are, and in regards to pet store fish, they were once brought from the wild, but most pet store fish are domestically bred and have been developed for certain traits for awhile.
I hope it doesn't die. There's not a good reason for removing him, so now that you have, hopefully you can provide good care.