Gill mycosis of the torpedo ray

What is it?

Gill mycosis is a fungal infection (caused by microscopic fungi) that affects the gills, the respiratory organ of cartilaginous fish such as the torpedo ray. It develops mainly in weakened animals or kept in poor quality water, in aquariums or transit tanks. The fungi invade the gill tissue and seriously disrupt gas exchange, putting the animal in respiratory danger. This disease remains rare in the wild but can appear during capture, transport or prolonged stays in captivity.

Affected torpedo rays show abnormally rapid or labored breathing, with accentuated opercular movements (at the level of the gill slits).

The animal may swim disorderly, frequently rise to the surface or remain at the bottom without moving.

Commonly observed signs

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

Transmission

Transmission occurs mainly through water contaminated by fungal spores, favored by promiscuity between animals and poor quality water.

References

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

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