All animals can benefit. Form deer to fish, they all can. Fish compost (yuck) produces the sand that is on the beach and in the ocean, creating a soft, light, sandy environment for fish, crabs, snails, etc. And deer compost, creates good soil for plants to grow in, and so animals have plants to consume, which means the carnivores have plenty to eat. SO, all animals benefit from the ecosystems created from composting.