The Aeromonas are bacteria that negatively affect the health of freshwater fish, being responsible for infections that can be fatal if not treated properly. These bacteria can be found in domestic aquariums, fish farms and natural bodies of water. Aeromonas They are opportunistic, attacking when water conditions are unsuitable or when fish are under stress.
There are two main types of aeromonas that commonly affect fish: Aeromonas salmonicida y Aeromonas hydrophila.
Aeromonas salmonicida
This type of bacteria is particularly known for causing furunculosis in fish, a disease that especially affects salmon, but also other freshwater species. Aeromonas salmonicida It is a gram-negative and psychrophilic bacteria (it grows at low temperatures), which makes it even more dangerous, especially in aquariums or fish farms where cold water prevails.
Symptoms in infected fish include:
- Hemorrhages in the muscles.
- Swelling of the skin.
- Noticeable external bleeding, including fish excrement.
The disease progresses rapidly, and if not detected and treated in time, it can lead to the death of the fish in just 2 or 3 days. This infection is usually related to deficiencies in water maintenance, as well as situations of continuous stress in the fish.
Aeromonas hydrophila
La Aeromonas hydrophila is another type of bacteria that, in addition to affecting freshwater fish, can infect reptiles, amphibians and even mammals, including people. It is the cause of diseases such as hemorrhagic septicemia, which severely weakens fish and can spread rapidly in an aquatic environment.
This bacteria can cause two types of infections:
- External infections: They manifest themselves with fin rot, which begins with slight fraying until the fins completely disintegrate.
- Internal infections: They affect organs such as the kidneys, causing fluid retention and abdominal distension, which in severe cases can lead to dropsy. Other signs include separation of scales and exophthalmos (swollen eyes).
It is important to note that these infections are usually triggered in environments where water quality is poor. Overcrowding de peces, the lack of oxygenation and the accumulation of organic waste create the perfect environment for the proliferation of Aeromonas hydrophila and other pathogenic bacteria.
Treatment and improvements to the aquatic environment
Treatment of infections by Aeromonas It is done by improving the conditions of the aquarium or pond. The main factors to take into account are:
- Water quality: Perform partial water changes frequently to ensure that parameters such as pH, temperature and filtration are in optimal condition. It is essential to avoid the accumulation of waste and food remains that can promote the proliferation of bacteria.
- Adequate nutrition: Provides live food and vitamin supplements to strengthen the fish's immune system.
- Use of antibiotics: In severe cases, specific antibiotics may be used. It is recommended to avoid the use of penicillin, since the bacteria Aeromonas are resistant to this type of treatment. Instead, drugs such as sulfonamides, oxytetracycline or chloramphenicol can be used under the supervision of a specialized veterinarian.
It is essential to implement preventive practices, since infections by Aeromonas may have a high recurrence rate if underlying causes, such as overcrowding, are not adequately managed de peces and poor water conditions.
Preventing infections in aquariums and hatcheries
One of the most effective ways to avoid diseases caused by Aeromonas is to maintain a routine of care and cleaning of the aquarium. A clean environment not only promotes the health of the fish, but also reduces the chances of a pathogen thriving.
The following best practices can help prevent bacterial infections in fish:
- Maintaining water quality: Test your water regularly to monitor ammonia, nitrite and nitrate levels. Water should be clean, well oxygenated and free of contaminants.
- Avoid overcrowding: The aquarium should not be overpopulated, as close contact between fish can facilitate the spread of diseases.
- Stress management: Stress weakens the immune system of fish, making them more susceptible to infections. Make sure to provide them with a calm environment, with enough space and hiding places.
- Use of probiotics: Probiotics can contribute to the intestinal health of fish and strengthen their immune system, as well as compete against pathogenic bacteria such as Aeromonas hydrophila.
Antibiotic resistance in Aeromonas hydrophila
A growing problem in the treatment of infections caused by Aeromonas hydrophila It is antimicrobial resistance. This bacteria has been shown to be able to resist many antibiotics, which complicates its treatment in aquaculture and hatcheries. de peces trade.
Strains of Aeromonas hydrophila They can transfer resistance genes to other bacteria, which poses a serious risk in systems that rely on antibiotics to control infections. For this reason, it is crucial to perform bacteriological analysis before starting antibiotic treatment in order to select the most appropriate drug and reduce the possibility of developing resistance.
The irresponsible use of antibiotics not only affects aquaculture, but also represents a danger to human health, since Aeromonas It can also cause infections in people, especially if they consume contaminated food or come into contact with aquatic environments where the bacteria is present.
In summary, the Aeromonas are highly dangerous bacteria for freshwater fish, but with proper maintenance practices, water quality control, and specialized medical care, it is possible to prevent and treat infections. Paying attention to fish stress, avoiding overcrowding, and performing frequent water changes are key to maintaining a healthy, disease-free aquarium. Although bacteria Aeromonas They are resistant to some antibiotics, so proper resource management and veterinary advice can make a difference in fish survival and the sustainability of aquatic facilities.