That would be a Polypterus Endlicheri. As for the clown loach, it might be fine for some time, but the problem would be that the endli could grow much faster than the clown loach and begin to see it as food, and if it tries to eat it that could end in the death of both fish.
Oh geez, I didn't read very carefully. Didn't realize that the fish was 4", looked smaller than that. Yeah, I'd agree with benzjamin on this one, that's pretty risky.