Like the father in “Finding Nemo,” anemonefish dads will do almost anything to support their offspring. Their parenting instincts are so strong that if you give a bachelor anemonefish a scoop of anemonefish eggs from an unrelated nest, he will care for them—constantly nipping at them to remove debris and fanning them with oxygen-rich waters—as if they were his own. (Any other fish would eat them, researchers say.)