Frozen beefheart cubes always made my catfish when smaller go nuts! Actually if I toss a few in as a treat, as big as they are now, they still love them
My ID sharks go through periods of not eating. I have learned not to panick. My large one (26" 16+ years old) did not eat for almost a year when I put him in his new pond. They will often bang themselves up. Use aquarium salt for all injuries and sickness.