Catfish ate my shark?

I just bought a red finned shark and an upside down catfish yesterday. The catfish is smaller than the shark. I always keep new fish quarantined for a little bit before putting them into my normal tank to keep them from spreading anything back and forth just in case. Anyway, they were doing well together this morning, minding their own business. I came back upstairs to sleep and noticed that my shark is gone? The catfish is just peacefully swimming around. I took the catfish out to deep search the whole tank, and no sign of the shark anywhere, it’s like he never existed, no fins left, nothing. Is it possible my (smaller) catfish ate the larger shark?