Nurse shark pneumonia

What is it?

“Nurse shark pneumonia” is a term used pictorially to designate damage to the respiratory system in the nurse shark, a species living in aquariums or in a natural coastal environment.\n\nUnlike mammals, sharks do not have lungs: they breathe using their gills. We are therefore rather talking about a gill and respiratory infection or inflammation, which disrupts gas exchanges in the water.\n\nThis condition mainly affects animals kept in captivity, in ponds or aquariums, where water quality and stress play an important role in its appearance.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

The main causes are opportunistic bacteria present in the water, which take advantage of a drop in the animal's defenses to infect the gills and associated respiratory tissues.\n\nFungus or gill parasites may also be involved, sometimes in association with a secondary bacterial infection.\n\nPoor water quality (insufficient oxygen levels, excess organic matter, chemical imbalance) is very often the underlying triggering factor.

The stress linked to captivity, transport or handling weakens the immune system of the nurse shark and makes it more susceptible to infections.\n\nPoor quality, poorly filtered or insufficiently oxygenated water is a major risk factor in aquariums.\n\nOvercrowding in a tank, an unsuitable diet, or the presence of pre-existing skin wounds also favor the appearance of the disease.\n\nYoung, recently captured or recent animals transferred to a new environment are particularly vulnerable.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Treatment

Treatment is based on immediate correction of water parameters, often the top priority to relieve the animal.\n\nDepending on the agent identified, an antibacterial, antifungal or antiparasitic treatment adapted to the aquatic environment can be implemented by the veterinarian.\n\nSupportive care, such as improving the oxygenation of the pool or temporary isolation of the animal, often accompanies the specific treatment.

Prevention

Possible complications

Without treatment, the infection can worsen and lead to severe respiratory distress or even death of the animal.\n\nA generalized infection (sepsis) can occur if bacteria enter the bloodstream from the affected gills.\n\nChronic stress linked to the disease can also further weaken the immune system, favoring other secondary infections.

When to see a veterinarian

Prognosis

The prognosis is favorable if the disease is detected early and if the water parameters are quickly corrected in parallel with medical treatment.\n\nIn the absence of treatment, the outcome can be unfavorable, particularly in animals already weakened by stress or other diseases.

Frequently asked questions

References

WOAH — Organisation mondiale de la santé animale (ex-OIE)

Content reviewed by the TunisieVet editorial team · Updated 25 September 2026