Your catfish may be reproducing but the fry are being eaten in no time by predator fish. Catfish fry are easily preyed about as they initially swim around in dense balls of fish. On the other hand, catfish need hiding places to spawn in and if there are none then spawning is negligible. Commercial farms use milk cans etc.

Provided cover like milk cans could solve both of your problems.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.