It is characterized by an elongated, segmented body, a flattened shield-like brownish carapace covering two thirds of the thorax, and two long filaments on the abdomen.

Triops longicaudatus is found in fresh water ponds and pools, often in places where few higher forms of life can exist.

Triops longicaudatus is a member of the crustacean class Branchiopoda, which primarily contains freshwater animals with gills on their legs.

[1] Triops longicaudatus is usually greyish yellow or brown in colour, and differs from many other species by the absence of the second maxilla.

Apart from Triops cancriformis, it is the only tadpole shrimp species whose individuals display as many as three reproductive strategies: bisexual, unisexual (parthenogenetic), and hermaphroditic; see below.

[2] The head of Triops longicaudatus is typical of crustaceans and consists of five segments, but there is a tendency toward reduction of cephalic appendages.

Zoologists find it difficult to decide where the thorax stops and the abdomen begins; the debate is seemingly endless.

[3] The anterior thorax consists of eleven segments, each bearing a pair of appendages, called thoracopods or pereiopods.

At the end of the body is a pleotelson (fusion of the last abdominal segment and the telson) connected to long, multisegmented uropods.

The eggs are released in batches, have a thick shell, and can stand freezing temperatures as well as drought, enabling the population to survive from one season to the next.

The eggs have to dry out completely before being submerged in water again in order to hatch successfully; they may remain in a state of diapause for up to 20 years.

These eggs may have helped Triops longicaudatus, as well as other notostracans, to survive the various natural disasters and mass extinctions to date.

[1][4] To complete their lives, tadpole shrimps depend on the changing nature of the temporary waters they inhabit.

As the pool fills with rainwater during the winter and spring, they hatch and feed on fairy shrimps and other invertebrates.

The number of segments and appendages increases as Triops grow, and they slowly change to greyish brown.

It is most active at a temperature of approximately 20 °C (68 °F), and is usually found scratching the mud at the bottom of pools, searching for benthic food.

Loose food particles are collected in a groove running down the underside of the body lengthwise, and held together by a sticky secretion until they are swallowed by their very small (2 mm wide) mouth.

The tiny mouth is deep in its underbelly, and while the animal is capable of breaking up plant roots or dead fish, it is incapable of chasing down and eating prey larger than it is.

[6] The species is considered a human ally against the West Nile virus, as the individuals consume Culex mosquito larvae.

In Wyoming, the presence of Triops longicaudatus usually indicates a good chance of the hatching of spadefoot frogs.

They will often feed themselves by grazing on algae and other grunge from the bottom and sides of the tank and on small particles clinging to sponge filters or to Marimo moss balls, which are often cultured alongside Triops.