This jellyfish floats on the surface of the Pacific Ocean for most of its life. It starts out underwater during its larval stage and then floats on the surface throughout the rest of its life. The Velella or as we call them, sailfin jellyfish begin their lives in the middle of the ocean, sometimes after a prevailing wind, it will wash up on the shore in the thousands, l saw this last year on Vancouver Island. We were hiking on the northwest coast of the island and there were many thousands of them washed up on the beaches.
The sailfin jellyfish is carnivorous, but as it is not very large and its tentacles are not very long, it can only feed on tiny shrimp, plankton, and very small fishes that swim close to the surface. Its mouth is located in the middle of the underside of its body and it uses its tentacles to draw small fish to it. They, in turn, are eaten by floating snails, sea slugs, and sunfish.
The sail of velella stands up diagonally across the disc. Not all sails are the same though, some go from right to left and others from left to right. This means that the wind and wave movement will send them sailing off in different directions, spreading them to all parts of the ocean. They can be seen mostly in tropical and temperate waters, and often wash up on a beach, dying in huge groups, sometimes they wind up in the north Pacific and wash up on Vancouver Island. They are quite fascinating little creatures for sure.
Although Velella toxins are pretty harmless to humans, you should not handle them and then touch your eyes. The toxins on your fingers can bring on some severe itching and irritation.