Ostracods belong to the subphylum Crustacea, the same subphylum as crabs and lobsters. Ostracods love both in freshwater and in the ocean and the difference between the two forms are easily recognized so are very useful in deciding what kind of environment the rocks in which they are found was deposited. The ostracods of ancient Lake Florissant likely lived on the bottom of the lake and fed on organic matter in the sediment.
Living ostracods in your backyard
You can find living ostracods at your own home! Birds often inadvertently transport ostracods in their feathers when they bath in 
lakes, ponds, and streams then transfer them to household birdbaths. During spring and summer, periodically take some water from your birdbath after birds have had their fun. Put the water in a thin clear container (Tic Tac packages work especially well) and look at the water with a magnifying glass. Eventually, you will see little light-colored things swimming around, and if you have a powerful enough magnifier, you will see that they have little shells with fuzzy things hanging out one side (see picture at left).
