Parasitism by copepods and crustaceans parasitic on the nurse shark
The nurse shark (Ginglymostoma cirratum) can host various external parasitic copepods and crustaceans, such as certain species of the Pandaridae or Siphonostomatoida family. These small crustaceans cling to the shark's skin, gills or fins t...
What is it?
The nurse shark (Ginglymostoma cirratum) can host various external parasitic copepods and crustaceans, such as certain species of the Pandaridae or Siphonostomatoida family. These small crustaceans cling to the shark's skin, gills or fins to feed on mucus, blood or tissue. This disease mainly affects nurse sharks kept in aquariums or tanks, but also exists in the wild. A light infestation often goes unnoticed, while a significant infestation can weaken the animal.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The signs depend on the number of parasites present.
We can observe small dots or filaments visible to the naked eye, attached to the skin, the fins or near the gills. The shark may rub itself against the walls of the pool, rocks or sand to try to get rid of the parasites.
Skin lesions, irritated or slightly swollen areas may appear at the attachment points. The fins may appear damaged or frayed.
In case of a heavy infestation, the animal may show less fluid swimming, a reduced appetite and a general state of fatigue, particularly if the gills are affected, which can interfere with breathing.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The disease is caused by the attachment of external parasitic crustaceans (copepods and sometimes isopods) to the skin, fins or gills of the nurse shark. These parasites feed on the tissues, mucus or blood of the host using mouthparts adapted for attachment.
The risk increases in captivity when water quality is poor or when new animals or equipment are introduced without sufficient quarantine. Stress, a high density of animals in the same pond, or an insufficient filtration system also encourage the proliferation of parasites. In the wild, contact with other carrier fish or sharks is the main source of contamination.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The aquatic or exotic animal veterinarian visually examines the shark, if possible without excessive stressful handling. He can take a parasite or a sample of mucus to observe it under a microscope and precisely identify the species in question. The general condition of the animal, its swimming behavior and its appetite are also evaluated.
Treatment
The treatment uses external antiparasitic products adapted to elasmobranchs, used under strict veterinary supervision because sharks are sensitive to many chemical substances common in aquariums. Adjustment of water parameters and improvement of environmental quality often accompany medical treatment.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention is based on good water and pond management: effective filtration, regular monitoring of water parameters and appropriate cleaning. Quarantining any new animal before its introduction into a common pool helps limit the entry of parasites. Regular observation of the shark's skin and fins helps detect any abnormalities early.
Possible complications
Untreated infestation can lead to superinfected skin lesions, gill damage with difficulty breathing, general weakening and increased susceptibility to other opportunistic diseases.
When to see a veterinarian
Presence of points, filaments or small organisms visible on the skin or fins.
Repeated friction against the walls or floor of the pool.
Abnormal swimming, apparent shortness of breath, or swimming near the surface.
Loss of appetite or unusual fatigue of the animal.
Prognosis
The prognosis is generally good when the infestation is detected early and treated by a specialist veterinarian. In the event of significant damage to the gills or infectious complications, the prognosis becomes more guarded and rapid treatment is necessary.
Frequently asked questions
Can these parasites be transmitted to humans?
No, the copepods and crustaceans parasitic on the nurse shark are specific to fish and sharks. They do not represent a known risk to humans.
Can you remove parasites yourself?
It is not recommended to handle a shark to remove parasites without the advice of a veterinarian, as this may injure the animal or worsen the lesions. A professional must assess the situation.
How do I know if my nurse shark is infested?
The main signs are visible dots or filaments on the skin, rubbing against the decor and sometimes changed swimming or appetite. A veterinary examination confirms the diagnosis.
Are nurse sharks in captivity more at risk?
Yes, life in ponds promotes transmission between animals and the proliferation of parasites if water quality or quarantine are not well managed.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 30 October 2026
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