The genus Chirocephalus belongs to an order of fairy shrimps (Anostraca) and contains a little over 50 similar species. Two species are present in Slovenia, namely C. croaticus and C. diaphanus. The body is elongate and in most species it does not exceed three centimeters in length. Both species present in Slovenia reach one and a half centimeters at most. They are transparent with parts of the body in hues of brown, green, blue and pink.

The body consists of a head (cephalon), thorax and abdomen. Head segments are fused while the thorax and abdomen are clearly metamerically segmented indicating the ancient origin of these animals. The carapace is absent, and the exoskeleton is thin and flexible.

The head consists of an acron and first five body segments. A pair of stalked compound eyes and a single median naupliar eye are located on the head. The head also bears two pairs of antennae (antennae I and II). The antennae I are short, while the antennae II are long and sexually dimorphic. In males they are enlarged and modified for grasping the female during mating. Mouthparts comprise a pair of mandibles, a pair of maxillae I and a pair of partially reduced maxillae II.

The thorax consists of eleven segments (thoracomeres) each carrying a pair of thoracic appendages (thoracopods). These are biramous, phyllopodous and armed with setae. The exoskeleton of appendages is very thin, and the support is mainly provided by the turgor of the body fluid. The thoracopods are used for respiration, swimming and feeding. A ventral canal, located medially between the thoracopods, has an important role in feeding.

The abdomen consists of eight posterior body segments (pleomeres) and a telson. Due to the absence of appendages, the abdomen resembles “a tail”.  The first two abdominal segments are fused and carry a genital opening (gonopore), a pair of penes in males and an ovisac in females. The telson is bifurcated into a caudal furca, which is used in swimming for steering.

Fairy shrimps of genus Chirocephalus have palearctic distribution and are present in Europe, Asia and north Africa. C. diaphanus is distributed throughout Europe, while the C. croaticus is endemic to Croatia and Slovenia with the last large population in Lake Petelinje. Anostracans generally thrive in various extreme environments. Such are also both Slovenian species, which can be found in different ephemeral freshwater bodies, where they are without competitors for food sources and safe from predation. They inhabit intermittent lakes, ponds and puddles in karstic terrain and mountains. The water is present in such environments only part of the season, since it drains into the underground and evaporates during summer in karst and freezes in the mountains during winter. Anostracans are well adapted for difficult conditions in their environment. They have very resistant and against desiccation protected eggs, which they deposit into the sediment. Their lifecycles are short usually taking less than three months. Due to their short-lived presence, they are rarely observed.

Two other anostracan species are present in Slovenia. One is Branchipus schaefferi which has a similar distribution and inhabits similar habitats as C. diaphanous. Another is the cosmopolitan brine shrimp (Artemia salina) which lives in saline lakes and salt evaporation ponds. In Slovenia the brine shrimp is present only in Sečovlje salt pans. They are adapted to a wide range of salinities and can survive in water with six times greater salinity than the salinity of the Mediterranean sea. In favorable conditions they reproduce parthenogenetically and quickly reach high numbers of individuals. The water they live in then acquires a pink hue due to the carotenoid pigments they contain and obtain from algae they feed on. In flamingoes that feed on brine shrimp the plumage consequently obtain pink coloration. The brine shrimp eggs can be obtained from pet shops and relatively easily reared to nauplii (larvae), which are a good food source for fish and other aquarium animals.

Anostracans generally swim with the ventral side up and only rarely rest on the bottom. They swim smoothly with metachronal beating of their phyllopodia. In danger they can evade in a jump like fashion with contractions and extensions of the whole body. They are filter feeders, creating water current with their phyllopodia in the ventral channel between them and catching plankton and detritus on the setae on phyllopodia. During mating the male grabs a female with his second antennae. A pair then swims together often for a few hours, until the male fertilizes the female.