Cyclops are crustaceans and related to lobsters, crabs and shrimp. They are invertebrates with a hard outer shell. They swim freely about.

The cyclops has 5 pair of legs and a divided tail-like appendage called a furca. The Cyclops is very small about 2-3mm long with one black or red eye in the middle of its head. The cyclops is named after the one-eyed monster of Greek legend. It is greenish, straw yellow, or grayish in color. It goes jerking through the water usually in very large numbers. The females carry the eggs (shown in picture) in little side sacs and they multiply rapidly. The cyclops is often seen near water fleas or Daphnia. Many water animals feed upon the cyclops. It has a very important role in the food chain.