A pair of nudibranch feeding on algae, Papua New Guinea.

papua new guinea risbecia tryoni algae animal markings animal themes animals in the wild aquatic cerata close up color image coral coral reef eating front view gastropod horizontal ichthyology invertebrate living organism marine biology mollusk nature no people nudibranch outdoors photography reef rhinophore science sea sea life sea slugs species spotted tropical climate two animals undersea underwater wildlife zoology