Bacterial skin ulcerations of the torpedo ray
Bacterial skin ulcerations are a common condition in torpedo rays kept in aquariums or display tanks. They result in open lesions, often located on the disc (the flattened body) or near the eyes and respiratory orifices (spiracles). This di...
What is it?
Bacterial skin ulcerations are a common condition in torpedo rays kept in aquariums or display tanks. They result in open lesions, often located on the disc (the flattened body) or near the eyes and respiratory orifices (spiracles). This disease mainly affects animals weakened by stress from capture, transport or poor water quality. It can progress quickly if it is not taken care of, because the stingray skin plays an essential role as a barrier against the surrounding water.
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 first signs are often discreet: a small area of paler, reddened or slightly swollen skin. Over time, a real sore can appear, sometimes covered with a whitish or grayish deposit corresponding to dead tissue or an accumulation of altered mucus.\n\nThe ray may rub against the bottom or walls of the pelvis, a sign of discomfort or itching. It sometimes swims less smoothly, stays on the bottom longer than usual, or shows a lack of interest in food.\n\nIn more advanced cases, the skin around the wound may thicken, blacken or necrotize (die), and the animal becomes despondent, with sometimes more pronounced breathing in the spiracles.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
These ulcerations are caused by opportunistic bacteria naturally present in seawater, such as certain species of the Vibrio or Aeromonas genera. These bacteria take advantage of a break in the skin, caused by trauma, a handling injury, or contact with an abrasive surface, to colonize the tissues and trigger an infection.\n\nStress plays a central role: a ray that is poorly acclimatized, transported without precaution, or kept in water of insufficient quality sees its natural defenses weaken, which promotes bacterial proliferation.
Water whose parameters (temperature, salinity, ammonia or nitrite levels) are poorly controlled is the main risk factor. An overcrowded pool, a lack of space for the animal, or rough surfaces (bottom of the pool, decorations) also increase the risk of initial injury.\n\nStress linked to a recent capture, prolonged transport, or aggressive cohabitation with other fish or rays also favors the appearance of these lesions. Young animals or animals that have recently arrived in a structure 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.
The veterinarian specializing in aquatic or exotic animals visually examines the lesion and assesses its extent. He can take a sample from the wound (swab or biopsy) to identify the bacteria in question by bacteriological culture, which helps guide the choice of treatment.\n\nMonitoring the parameters of the pool water is an integral part of the assessment, because the quality of the environment often determines healing.
Treatment
Management is generally based on local wound care (cleaning, application of antiseptic products adapted to the aquatic environment) and, if necessary, antibiotic treatment generally or in a bath, chosen according to the results of the bacteriological analysis. Improving water quality and reducing stress are an integral part of the treatment.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
The best prevention is based on rigorous management of water quality: regular monitoring of temperature, salinity, and chemical parameters of the water. A well-sized pool, with a smooth bottom and no sharp edges, limits the risk of injury.\n\nIt is recommended to limit direct handling of the animal and to favor gentle capture methods during transfers. A period of quarantine and observation for any new individual introduced makes it possible to identify an emerging lesion early.
Possible complications
If left untreated, the infection can spread deep and affect underlying muscles or organs. Sepsis (generalized infection) is possible in a very weakened animal, which can lead to death. Scars or deformities of the skin may persist even after healing.
When to see a veterinarian
Appearance of a wound, redness or abnormal deposit on the skin of the ray.
Unusual behavior: the ray rubs against the scenery or remains motionless at the bottom.
Prolonged loss of appetite or marked depression.
Rapid worsening of an already known lesion, with blackening or enlargement.
Prognosis
The prognosis is favorable if the lesion is identified early and treated quickly, with correction of breeding conditions. On the other hand, an advanced infection or septicemia clearly worsens the prognosis, particularly in an already weakened animal.
Frequently asked questions
Is this disease contagious to other fish in the pond?
The bacteria involved are often already present in the water. The main risk remains contamination from another open wound in another weakened animal, rather than direct contagion.
Can you treat an injured torpedo ray yourself?
No, it is strongly recommended not to intervene alone. The torpedo ray has an electrical organ that can deliver a shock, and improper treatment can aggravate the wound.
How long does the healing take?
This varies depending on the size of the lesion and the general condition of the animal, ranging from a few weeks for a superficial wound to longer for a deep lesion.
How can we prevent this from happening again?
Maintaining stable and suitable water parameters, as well as an environment without abrasive surfaces, greatly reduces the risk of recurrence.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 25 September 2026
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