Africans...no. Pbass...maybe.
The main concern is to make sure there is NO chance of the gulpers mistaking the bass for food...considering there is a thread about a gulper eating an 8" leichardti arowana.
Personally, I've had luck with small tankmates with my gulpers. I have a couple of Panaque maccus in with mine, as well as some guppies, and they show no interest what so ever.