A water flea is only distantly related to land fleas, but gets its name from its flea-like movements.
The water flea is a microscopic crustacean that gets its nickname from the jerky, flea-like movements it makes while swimming. A member of the genus Daphnia and the order Cladocera, the crustacean is only remotely related to terrestrial fleas. In 2011, more than 600 species were described and catalogued, and many more are expected to be identified.
Water fleas consume organic matter found at the bottom of streams, as well as bacteria floating in the water.
The body structure of the crustacean, an arthropod, is similar to that of other insects in that it is divided into segments. However, these separate areas are difficult to detect in most water flea species because the segments tend to be nearly or completely fused. Like other insects, this organism has an exoskeleton and three to six pairs of legs. They have compound eyes and antennae. Its head is usually angled downward towards the rest of its body, a split typically indicated by a small notch or groove.
Water fleas live in various aquatic environments such as rivers, ponds, freshwater lakes, and streams. Some species live in acidic swamps. They are, however, mostly freshwater dwellers.
Ground fleas, which bite and suck blood from humans and animals, are different from water fleas.
Various species have different life cycles and life spans. Their longevity generally depends on the temperature of their aquatic environment. The average life expectancy for the different daphnia species ranges from 29 to 108 days, with the maximum life expectancy not exceeding one year.
The feeding habits of the water flea are similar to those of many aquatic creatures. Depending on their species and location, they eat various small organisms, such as small crustaceans and rotifers, and organic particles and algae-like creatures from the water in which they live. The crustacean is a filter feeder that consumes organic debris such as bacteria floating in the water. They also consume organic matter found at the bottom of lakes and streams. As part of the aquatic life cycle, fish and frogs often feed on water fleas.
Some water fleas live in acidic swamps.
Most water fleas are asexual and reproduce by parthenogenesis, which means that embryonic growth and fertilization occur without the need for male fertilization. In some species and under certain conditions, males, which are considerably smaller than females, are required to fertilize the eggs. This is, however, the exception. While some species are abundant, others are in danger of extinction. The stability of a certain population depends on the conditions of the place where the species resides.