Catfish: A father sea catfish keeps the eggs of his young in his mouth until they are ready to hatch. He will not eat until his young are born, which may take several weeks. Wow! I'd like to see Homer Simpson try this one...he can't make it an hour without eating a doughnut or drinking a beer!
Cockroach: A father cockroach eats bird droppings to obtain precious nitrogen, which he carries back to feed his young. Beaver's dad, Ward, was pretty dedicated...but I don't see him be willing to eat bird poop! Do you?!