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Nurse Shark
Ginglymostoma cirratum
The nurse shark (Ginglymostoma cirratum) is a sluggish, epibenthic carpet shark native to the coastal Atlantic and Pacific Oceans. Recognized by its long barbels, hinged mouth, and rounded dorsal fins, this nocturnal predator rests on the sea floor during the day and hunts small fish and invertebrates at night.
Water Temperature
24 - 28 °C
pH Value
8.1 - 8.4
Water type
Freshwater
Tank level
Bottom
Adult size
430 cm
Minimum tank volume
>= 500 L
Minimum group
>= 1
GH
15 - 25 dGH
KH
7 - 12 dKH
TDS
295 - 495 ppm
Conductivity
461 - 773 uS/cm
Species description
Geographical Origin and Habitat: Widely distributed in the warm waters of the Atlantic Ocean and the Eastern Pacific. Inhabits shallow coral reefs, mangrove channels and sandy plains. It is a sedentary benthic predator.
Taxonomy and Morphology: Nurse Shark. Corpulent and massive elasmobranch that grows slowly to cyclopean proportions: over 4 meters (13 feet) and 300 kg of weight. Tiny terminal mouth placed under a pair of sensory barbels ("mustaches"), used to flush out crustaceans.
Social Behavior: Indolent, placid and nocturnal. In nature, during the day they mass together in close groups, sleeping piled on top of each other under the reef caves. At night they actively patrol the seabed, generating powerful coughs to suck up hidden prey.
Coloration and Sexual Dimorphism: Uniform yellowish-brown color (young present small dark spots destined to disappear). Very rough skin, covered with dermal denticles similar to sandpaper. Males develop long claspers (cylindrical reproductive organs) between the pelvic fins.
Care, breeding and tankmates
Aquarium Setup: EXCLUSIVELY FOR PUBLIC AQUARIUMS. Absolutely impossible and illegal to keep in home tanks (although pups are cruelly sold in the American aquarium market). Requires circular concrete pools of 100,000 liters (25,000 gallons) and up.
Diet and Feeding: Carnivore (durophagous). Feeds by sucking the prey with a force equal to an industrial vacuum cleaner. In public aquariums it consumes kilos of whole squid, lobsters, octopus and thick fish fillets. They have a formidable appetite.
Water Quality: Being waste machines, they require mammoth foam fractionation systems (Industrial skimmers) and powerful Ozone and UV disinfection systems. Tropical marine water: 24-28°C (75-82°F), SG 1.020-1.025. A drop in oxygen is quickly fatal for animals this big.
Compatibility and Cohabitation: In public aquariums it is placed in the "Predator" ocean tanks. Cohabits with blacktip reef sharks (Carcharhinus), giant groupers and stingrays. Will swallow anything slow or injured that comes into contact with its snout.
Aquarium Breeding: Ovoviviparous. Captive breeding is extremely rare due to the immense tanks required to complete the mating ritual (in which the male violently bites the female to immobilize her). Pups are born live and fully formed at about 30 cm (12 inches) in length.
Risks and Diseases: The risk is linked to the compulsive purchase of this creature by private individuals who condemn them to hardship and bone deformities in tiny cubic tanks. The jaws of the nurse shark do not cut, but crush: a defensive bite disintegrates the bones of a hand.
Geographic Origin and Distribution
Widely distributed in the warm waters of the Atlantic Ocean and the Eastern Pacific. Inhabits shallow coral reefs, mangrove channels and sandy plains. It is a sedentary benthic predator.
Origin
Tropical oceans and reefsNorth AmericaEast Asia
Fish profile
- Temperament
- Semi-aggressive
- It is generally docile. It can bite defensively if provoked. It is an active nocturnal hunter.
- Diet
- Omnivore
- It is a large carnivore. Feed fresh or frozen seafood. Vitamin supplements are absolutely necessary.
- Life expectancy
- 25-30 years
- In captivity, within large public aquariums equipped with professional filtration and life support systems, this species has a life expectancy ranging from 25 to 30 years. In the wild, they can live even longer, sometimes exceeding 40 years. The key to their longevity lies in absolute stability of saline and thermal parameters.
- Adult size
- 430 cm
- The catalog's scalar value is 430 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 430 cm for this species, recorded as total length (TL). The taxonomic record consulted is Ginglymostoma cirratum (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Flexible
- It is kept solitarily. Public aquariums keep one male with females. They tolerate their own kind.
- Feeding frequency
- Twice daily
- It requires less frequent feeding. Feed two to three times weekly. Overfeeding causes severe water degradation.
- Bioload
- This predator produces an immense bioload. Industrial-sized filtration is mandatory. Frequent large water changes are required.
- Flow
- Stagnant
- It prefers moderate water flow. Flow must keep detritus suspended. High dissolved oxygen is critical.
- Reproduction
- Oviparous
- It gives birth to live young. Captive breeding requires massive facilities. Mating involves aggressive biting behavior.
- Compatibility & tankmates
- It will eat smaller fish. Keep it in species-only setups. It is unsuitable for standard reefs.
- Tank level
- Bottom
- It is strictly a bottom-dweller. A massive floor space is essential. Provide large caves for hiding.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 4.2 ± 0.2 se
- Resilience
- Low (4.5 - 14 years)
- Phylogenetic uniqueness (PD50)
- 0.8125
- Bayesian Length-Weight
- a = 0.00417, b = 3.08
- VulnerabilityVery high vulnerability (90 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
