You should give it to him with other fish feed. It is not good to feed it with a single nematode all the time, and it is easy to feed it greedily. Don't always feed him or feed him too much at once. Red carp has no hunger, so eat as much as you feed. It is estimated that you fed him too much, so his stomach became bigger and his scales became warped. It's okay. Be careful in the future.