He nips, which means you need a Really well decorated tank. Think, plant/decorate until you can't see the gravel(very well). Don't add more fish until you can provide for your current catfish, who needs more placed to hide.
Be sure to inspect your catfish routinely, a betta can kill another fish.
Okay, thanks. How would I clean the gravel if everything is on top? I'm guessing the waste would be on top too, but I'm asking just incase, I dunno, maybe some of the waste could still get stuck among the gravel?