So i was thinking of putting black bullhead catfish in a pond because they are delicious but problem is that the have growing stunt at a 300 g so i really dont know what to do.does somebody know how to overcame it

300g (or .6 lb) is below average for an adult bullhead. If you stock them in your pond they may do better if you stock a few less than recommended to allow for them to grow.

In general however, bullheads don't grow very big. They max out around 700-900g (1.5-2 lb)

matija, bullheads over populate quickly and stunt. Have you considered Channel Catfish, and/or using quality commercial fish food?

We dont have channel but we have wls catfish