1 kinds · tap one for a closer look
Peaceful, but can catch tiny shrimp.
Shops often swap the names: Cambarellus shufeldtii is the Cajun dwarf crayfish and C. puer is the swamp dwarf. The smallest of the group is C. diminutus.
288 species in our list are a good match.
Peaceful, but can catch tiny shrimp.
Check your local laws. EU: not on the Union list of invasive alien species (listed crayfish: Procambarus clarkii, P. virginalis, Pacifastacus leniusculus, Faxonius limosus, F. virilis, F. rusticus, F. immunis, Cherax destructor). Native to the USA; no US federal restriction found. As a North American crayfish it can carry crayfish plague (Aphanomyces astaci), deadly to European, Australian and New Guinea crayfish: never release animals or tank water, and keep apart from Cherax (Garnelio). Check the rules where you live before you buy one, and never release it into the wild.
Powdered food, wafers and blanched vegetables.
Tap a food to see what it is.
Form I males have hooks on the 2nd and 3rd walking legs and V-shaped gonopods where the carapace meets the tail; females are slightly larger.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Direct developer: females lay 20-40 eggs depending on size; fully formed young hatch after 4-6 weeks and stay under the mother 1-2 days. In the wild it breeds year-round in SE Louisiana; most males first breed in their second season.
Keep a group with more females than males.
20-40 L tank with many hides, plants and moss.
Warm water and good feeding.
20-40 eggs (depending on female size); young hatch after 4-6 weeks.
Juveniles look like tiny crayfish; feed powdered food and moss.
A small, very variable (striped or spotted, orange-red to grey-brown) swamp dwarf crayfish from the southern USA that suits planted nano tanks: it neither digs nor eats healthy plants. It is rare in the trade and is not the smallest dwarf crayfish (C. diminutus is smaller).
Crayfish specialist Horton H. Hobbs Jr. described this tiny crayfish in 1945. It is one of the smallest crayfish in North America and is popular with nano-tank keepers.
First described by Horton H. Hobbs Jr. in 1945. Named for 'Puer' is Latin for boy, referring to its small size.
16 facts checked with sources
Invertebrate (freshwater dwarf crayfish, family Cambaridae, North/Central America). Cambarellus (Pandicambarus) puer; valid (ITIS). Author year differs between sources (Wikipedia "Hobbs, 1941", Garnelio "Hobbs, 1945"); not resolved. Some NW Louisiana/SW Arkansas populations may be an undescribed species (NatureServe). NAME WARNING: common name is swamp dwarf crayfish; the legacy name "Dwarf Cajun crayfish" belongs to C. shufeldtii (Cajun dwarf crayfish).
USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013 · Wikipedia: Cambarellus puer (cites IUCN Red List: Alvarez et al. 2010; NatureServe)Legacy has no family; recorded as sourced.
Wikipedia: Cambarellus puer (cites IUCN Red List: Alvarez et al. 2010; NatureServe)Total length; rarely over 3.7 cm. Legacy 3.5 cm fits.
USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013 · Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Legacy 16-26 °C is almost the same; aquarium range 15-25 °C (Garnelio). Wild animals tolerate warm water.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German) · USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013Legacy 6.5-8 within 6-8.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Legacy had none. Source gives only an upper limit (GH up to 20); min left null.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Translation: from 45 L. Legacy 20 L is small. Single retail source.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Wild: about 15-18 months; aquarium (Garnelio): 2 years. Legacy "2 years" supported.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German) · USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013Translation: very peaceful for a crayfish; may crack snails; never mix with crabs or other crayfish. In the wild C. shufeldtii displaces it.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Translation: suitable for beginners.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Legacy has no range; recorded as sourced. Not collected in Oklahoma since 1975 (Morehouse & Tobler 2013).
USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013 · Wikipedia: Cambarellus puer (cites IUCN Red List: Alvarez et al. 2010; NatureServe)Legacy supported. Garnelio places the female opening at the 2nd walking legs, which conflicts with the usual crayfish pattern (3rd pair); not used.
USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013 · Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Legacy "Females carry 10-30 eggs" is lower than the retail figure (20-40). No wild egg counts found (wild egg diameter 1.0-1.1 mm).
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German) · USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013Legacy "10-30 eggs for about 3 weeks"; single retail source.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)Correction: legacy "the smallest common dwarf crayfish in the trade" is wrong (C. diminutus, the least crayfish, is sold as the smallest; even C. shufeldtii females reach only about 3.3 cm in the wild vs C. puer to 3.7 cm). Not found in the US pet trade (Faulkes 2015, via USFWS); traded in Germany and the Czech Republic.
Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German) · USFWS Ecological Risk Screening Summary: Swamp dwarf crayfish (Cambarellus puer), 2017, quoting ITIS, IUCN, NatureServe, Morehouse & Tobler 2013 · Garnelio product page (URL/title only, page not read)National/state rules not checked. USFWS screening: Medium FI-ISK invasiveness risk for the Czech Republic (Patoka et al. 2014).
Wikipedia: List of invasive alien species of Union concern (summarises EU Reg. 1143/2014 implementing lists 2016/1141 to 2025/1422) · Garnelio (German invertebrate breeder/retailer): Knabenkrebs - Cambarellus puer (German)