Sea Angels

ocean · molluscs · tiny creatures · see-through

Mysterious sea ghosts. Sea angels are small free-swimming sea slugs that look almost invisible because their bodies are see-through. They float and swim through the ocean in ways that remind people of little angels moving through water.

Six different families. Scientists have sorted sea angels into six separate families based on how their bodies are structured. Each family has its own special features and ways of living in the ocean.

Pelagic ocean dwellers. Sea angels live in the open ocean water (called the pelagic zone) rather than near the bottom or shore. They drift with ocean currents and are part of the plankton that feeds so many ocean creatures.

Part of molluscs. Sea angels belong to the mollusc group, the same large family that includes snails, clams, and squids. Even though they look nothing like those creatures, they all share similar body plans at the genetic level.

Once mistaken for pteropods. Scientists used to think sea angels were pteropods (another type of sea creature), but they later discovered sea angels are their own special group. This shows how ocean creatures can look similar but actually be quite different.