Phylum — Arthropoda.
Subphylum — Crustacea.
Class — Malacostraca.
Order — Decapoda.
Superfamily — Astacoidea
Family — Cambaridae.
Genus Cambarellus.
— Cambarellus diminutus [Hobbs, 1945] — Least crayfish. North America, Gulf of Mexico states. During the dry season, they burrow into wet mud. Freshwater crayfish. This smallest dwarf crayfish reaches a length of about 25 mm. Colors vary from brown, dark brown, dark reddish-brown with marble-like spots. They can be pale blue, and some very rarely have an intense blue color. The blue color in nature depends entirely on food and water.
An aquarium of at least 50 cm in length is required, with 15-20 liters per crayfish, divided by stones, caves, and driftwood into separate territories, inside of which there must be refuges and shelters for the crayfish. Dried beech, nut, walnut, and oak leaves are needed in the aquarium. Substrate of sand or fine gravel. Keep in a group. Slightly aggressive, but fights between them are rare; combining them with other species of crayfish is not recommended because one of them will win and injuries will occur.
They can be kept with large shrimp, but losses are possible. Fish should not be large and aggressive, otherwise, only a small part of the young crayfish will survive. It is desirable to have various mosses in the aquarium. The water must not contain nitrates and nitrites, because even a small amount can be fatal to crayfish. Weekly 25% water changes are necessary. Omnivorous, along with standard special foods for crayfish, they also take food tablets and pellets for fish, and small snails.
For breeding, they are placed in an aquarium with plenty of hiding places and a water temperature of 22-23°C, dH 5-10°, pH 7.5-8.0. Regular water changes with a temperature difference of no more than 2-3 degrees are very important for successful breeding. Females carry eggs for three to four weeks. They live for 2 years.
— Cambarellus montezumae [Saussure, 1857] — Montezuma dwarf crayfish. Mexico. 3-5 cm. Freshwater. Colors vary from brown to reddish-brown and greenish-brown, or dark gray to gray-blue, sometimes with two matte, wide stripes on the carapace and abdomen. During the first few months after birth, most young have a very light brown color. Colors become more intense with age and can change after each molt.
A young specimen or one after molting may look different, being striped. Several color and shape variations are also possible in this species. Females are larger, have shorter and wider claws and a wider abdomen, and their tail is wider. Males have thin, longer claws and a longer abdomen. In pregnant females, the stripes on the back are especially contrasty. The sides of the male’s body are lighter than those of the females. — Cambarellus montezumae var. “Choco” – Has a chocolate coloration of the entire body.
Very peaceful, do not attack fish and do not damage plants, making them suitable for community aquariums. This species does well in small aquariums. The crayfish needs lower temperatures than tropical fish. They eat dead fish. Substrate: fine gravel or sand. It does not place high demands on water values, feeling well in both soft and hard water. They eagerly climb plants, so plants should not reach 2-3 cm from the edge of the aquarium. Dense vegetation is needed. Various hiding places are important, with an entrance diameter of at least 2 cm. After the crayfish sheds its shell, it is completely helpless and must hide.
Active during the day. Pregnant females and older crayfish often hide for days at a time. Peaceful with conspecifics, adopt a threatening posture, minor skirmishes are possible. They eat bloodworms, shrimp food, peeled shrimp, tubifex, and dead fish. Can crossbreed with other species (C. patzcuarensis). They mature in 3 months at a size of about 2 cm. Breeding is very easy, females carry eggs under their tail for three weeks. Life span is about 18 months. T 15-30°C. dGH 8, pH 6.4-8.2.
— Cambarellus ninae [Hobbs, 1950] — Nina dwarf crayfish. USA, in Texas and Arkansas. Females 30-35 mm, males smaller and more slender. Color predominantly beige to brownish with light spots. However, there are some specimens that are somewhat reddish, as well as bluish. Females during the breeding period can change their color to dark brown, dark red, or dark blue. All specimens of Cambarellus ninae have distinct star-shaped spots.
Very peaceful creatures, males resolve conflicts among themselves without injuries. Aquarium 60 cm long, driftwood, stones, and dense vegetation, mostly mosses. Caves made of stone, wood, clay, or PVC pipes and foliage can be used as shelters. Can be kept with small fish. They reach sexual maturity in 3 months. Females carry up to 50 eggs, and young crayfish appear after just 14 days. Highly productive. They live 18-24 months. Water temperature slightly warmer: 22-26°C; dH 6-18°; pH 7.0-8.5.
Identification: Genus Cambarellus — Cambarellus diminutus, montezumae, ninae.
Cambarellus patzcuarensis, puer, shufeldtii.
Aquarium dwarf crayfish, Crayfish suitable for keeping with fish. 
