Mammals:
1. Blue Whale: The largest animal on Earth, found in all oceans.
2. Dolphin: Highly intelligent and social animals with a diverse range of species.
3. Sea Otter: The smallest marine mammal, known for its dense fur.
4. Manatee: Gentle herbivores found in warm coastal waters.
5. Whale Shark: The largest fish in the world, a gentle filter feeder.
Fish:
6. Clownfish: Colorful fish that live in anemones.
7. Seahorse: Unique fish with horse-like heads and a prehensile tail.
8. Tuna: Fast-swimming fish that are popular for sushi.
9. Anglerfish: Deep-sea fish with a bioluminescent lure to attract prey.
10. Octopus: Highly intelligent cephalopods with eight arms.
Invertebrates:
11. Starfish: Echinoderms with five arms and a unique ability to regenerate.
12. Jellyfish: Gelatinous invertebrates that drift through the water.
13. Sea Urchin: Spiny invertebrates that graze on algae.
14. Coral: Colonial invertebrates that form colorful reefs.
15. Sea Cucumber: Worm-like invertebrates that play a role in ocean floor ecosystems.