Frog and toad
Perhaps no group of animals contains so many dedicated fathers as frogs and toads. There are frog fathers that carry their tadpoles in their mouths, often refusing to eat until the tadpoles are old enough to survive on their own. Other frog fathers embed their spawn inside their skin, often on their backs or legs (such as with the aptly named midwife toad).
One frog species, called the pouched frog, has males that harbor a specialized pouch to carry the young while they mature, much as female marsupial mammals do. Who knew amphibians made such incredible dads?