water flea

American  

noun

1. any of various small crustaceans that move about in the water like fleas, as those of the genus Daphnia.

---

water flea British  

noun

1. any of numerous minute freshwater branchiopod crustaceans of the order Cladocera, which swim by means of hairy branched antennae See also daphnia

---

Etymology

Origin of water flea

First recorded in 1575–85

Example Sentences

But evidence of the potential effects of PVA “are scarce,” said Magni, who co-authored a study that did not find toxic effects associated with the compound in fish embryos and a species of water flea.

From Washington Post • Nov. 15, 2022

Daphne, named after daphnia, a type of water flea, credited with helping clear the waters of Lake Washington of blue-green algae after sewage stopped regularly flowing into the lake in the 1960s.

From Seattle Times • Mar. 27, 2021

This week Hintz published a new paper focusing on the fate of the water flea, a tiny critter that tends to thrive in such large numbers that it has a key influence on ecosystem health.

From Scientific American • Dec. 6, 2018

That testing involves students helping to constantly breed fathead minnows and Ceriodaphnia dubia, a species of water flea that is used in testing water quality.

From Washington Times • Sep. 11, 2017

It is even possible in some cases, the water flea, for example, for the female to produce young without the necessity of fertilization by the male.

From Astounding Stories, April, 1931 by Various