want to start a catfish farming on a small scale

You need a good supply of quality water and lots of room for the ponds. You need to make sure of the laws in your area relating to this kind of business, permits, licenses etc.. And you do need food food for the fish to grow fast. I would try to visit a catfish farm and find out as much from them as to what is working for them.

I'm not in the fish business, but I do know catfish tend to like the bottom of the ponds and they eat carrion. I would suggest starting out with tanks at home and then moving up to larger fish tanks in a warehouse, etc. But, I think, just to start, you can do this at home. I would check with your city or county about ordinances as to how big a tank you can have, etc.