Least Crayfish (Cambarellus diminutus 'Blue')

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Least Crayfish
Cambarellus diminutus 'Blue'
Least Crayfish (Cambarellus diminutus 'Blue')
Name Least Crayfish
Name Lat. Cambarellus diminutus 'Blue'
Family Crayfish
Family lat. Cambaridae
Order Decapoda
Order lat. Decapoda
Origin North America
Habitat Streams, pools
Diet Carrion, detritus, crayfish food
pH 6.5-8.0
Behavior Semi-aggressive
Keeping Individual, pair, group
Care Level Moderate
Reproduction Oviparous
Breeding Moderately difficult
Life Span 2-3 years
Protection No
Metric Units
Size 2.5 cm
Temperature 18-26 °C
Hardness 5-15 °dH
Aquarium 30 l
US Units
Size 1"
Temperature 64-79 °F
Hardness 89-267 ppm
Aquarium 10 gal

Distribution and habitat

The Blue Small Dwarf Crayfish is a cultivated form. The wild form is the Small Dwarf Crayfish, the smallest known dwarf crayfish species. The range is the southern United States and the states along the Gulf of Mexico. They live there in stagnant and slow flowing waters with dead wood and foliage.


They need a well-structured aquarium with roots, stones and plants, plus caves or crab tubes as hiding places and a moderate current. The substrate should be sand or gravel, partially covered with foliage (e.g. sea almond leaves, oak leaves).

No ammonia, ammonium and nitrite should be detectable in the aquarium water, the nitrate value should not exceed 100 mg/l. To ensure water quality and oxygen content, a filter and heater adapted to the size of the aquarium is required, as well as lighting for the species-appropriate day-night rhythm of the animals. When choosing the filter, special care should be taken to ensure that the animals cannot be sucked in.


They feed on animal organisms, carrion and dead plant material. They prefer live foods such as cyclops, daphnia and artemia, which are also accepted in frozen form, as well as food tablets, granulated and flake foods. Occasionally, plant food in the form of spirulina, kelp or scalded leafy vegetables should be offered.

Regular and varied feeding promotes health and prevents deficiency symptoms. Unaccepted food must be removed after 2-3 hours.

Behaviour and compatibility

Although loners, they behave little aggressive within the species, but also towards other crayfish. Keeping several pairs or groups is recommended in a much larger and richly structured tank. They can be socialized with shrimps, snails and smaller peaceful fish, but it is better to keep them in a species tank.

Basically, only mutually compatible animals with similar demands on water conditions and water temperature should be socialized.

Reproduction and breeding

Males can be identified by the gonopods (mating styli) on the abdomen of the underside of the body. During mating, shortly after molting, the female is turned onto her back by the male, which transfers a sperm package with its gonopods. The female carries the eggs (30-40 of them) on her pleopods (webbed feet) and supplies them with oxygen by movement (fanning). Dead or non-developing eggs are eaten by the female. The young hatch after about 4 weeks.


They are shy animals that usually explore the environment only towards evening and are therefore little seen during the day. It can happen that a dwarf crayfish is missing a claw. Usually these are females that have lost a claw during mating. The missing claw slowly grows back during the following molts.

The well-being of the animals should be checked regularly. Temperature should be checked daily, pH, hardness and nitrate levels at least every 14 days. Regular partial water changes are recommended, even if the contaminant level has not yet reached the upper limit. Sudden changes in water quality should be avoided. Newly introduced animals must be accustomed slowly to the water in the aquarium.

Further literature can be found in your pet store.


Text: Barbara Pachner; Image: Alex Rinesch

Source: LUKHAUP & PEKNY (2008): Süßwasserkrebse aus aller Welt, Dähne Verlag; ENGELMANN & LANGE (2011): Zootierhaltung - Tiere in menschlicher Obhut: Wirbellose, Verlag Harri Deutsch