I had a 30" channel cat that wouldn't eat anything live.
When he was younger and could still fit in his cave he would just suck in feeders and spit them out the other side to get them away from his cave.
But not everyone is as lucky as me so... consider them snacks as the cat gets larger.
Another thing to consider is that the channel cats mouth don't really get wide till about the 30" mark so you might be able to keep a full grown firemouth with one, but I don't think so.