Small water flea
Ceriodaphnia pulchella
Ceriodaphnia pulchella is a species within the Daphniidae family, widely distributed in stagnant freshwater bodies. It is significantly smaller than the common Daphnia magna and features a characteristically rounded body shape without a long posterior spine. As a filter feeder, it plays a central role in controlling phytoplankton levels and serves as an important food source for juvenile fish.
Details
Identification
Rounded carapace without a posterior spine, small head without a keel, short rostrum, terminal claw of the furca without secondary teeth.
Social behavior
Often occurs in high individual densities in the pelagic zones of lakes and ponds.
Diet
Feeds by filtering unicellular algae (phytoplankton), bacteria, and organic detritus.
Hunting strategy
Passive filter feeder; creates a water current with its thoracic appendages for food intake.
Spawning substrate
Eggs are carried in the dorsal brood chamber beneath the carapace.
Overwintering
Overwintering usually occurs as resting eggs (ephippia) in the sediment of the water bodies.
Ecology
Ecological role
Important primary consumer transferring energy from phytoplankton to higher trophic levels.
Natural predators
Planktivorous fish, predatory zooplankton (e.g., Leptodora kindtii), and insect larvae.
Competitor species
Other cladocerans such as Daphnia or Bosmina species, as well as rotifers.
Ecosystem service
Contributes to water clarity by reducing algal concentrations through filtration.
Threats
Eutrophication, pesticide input into water bodies, and acidification of habitats.
Scientific profile
Profile
Distinguishing features
Characterized by 7 to 9 spines on the postabdomen. The fornices (lateral head ridges) are often pointed. Unlike Ceriodaphnia quadrangula, the head of C. pulchella is smaller and the shell surface displays a fine reticulated pattern. A rostrum is absent.
Reproduction
Cyclical parthenogenesis: Rapid asexual reproduction occurs during summer months. Under deteriorating environmental conditions, males and resting eggs are produced.
Role in food web
Important link in the pelagic food web; converts primary production into animal biomass and serves as an essential food source for higher trophic levels.
Protection & threats
Status not on standard scale
Main threats
Anthropogenic eutrophication beyond natural levels, pesticide input from agriculture, and loss of small water bodies due to desiccation or infilling.