In aquariums, many diseases can be avoided if the maintenance of the aquarium is respected. Fish kept in good conditions will rarely get sick.
The golden rules to follow to avoid diseases
Regular maintenance of the aquarium: water change and filter cleaning. Water changes must be made with water at the same temperature as that of the aquarium, and with the same parameters. These two points are important because too cold water can easily trigger white spot disease. A water with different parameters entails a stress that can be the cause of diseases.
Respect the fish’s needs in terms of water parameters of the aquarium and in particular total hardness. They will not necessarily die in unsuitable water but will be prone to diseases.
Respect their requirements for places and hiding places. Needless to say, 2 discus kept in a 50 liter will develop diseases !!
In a community aquarium, you have to be very careful about the compatibility of the species between them. Similarly, the specific needs of certain species must be respected: groundfish must be kept in groups of 10 or more.
Do not overpopulate the aquarium: this generates stress and pollution.
Bring a varied diet to the fish: alternating dry and freeze-dried food, frozen food (previously carefully rinsed) and alive, fresh food like vegetables. Do not overfeed the fish either. You can add a vitamin supplement either directly in the water of the aquarium, or by impregnating the food.
Quarantine newcomers if possible. Many diseases are introduced into the aquarium with the arrival of new fish. When quarantine is not possible, preventive water treatment (eg EsHa 2000) can be done at the time of acclimatization of newcomers.
Avoid unnecessary stress. For example, avoid abrupt gestures during handling, do not let children tap on the glass.
By respecting all this, there is little risk of contracting a contagious disease. If, despite everything, an illness occurs, isolate the sick fish in a hospital. This avoids weakening healthy fish and unbalancing the aquarium with treatment. Obviously, if the disease reaches many fish, it will then treat the entire aquarium.
There are many targeted treatments for each disease. You have to be very careful about groundfish, such as corydoras or loaches, which are difficult to handle. If you have this kind of fish, you have to reduce the doses and lengthen the duration of the treatment. Salt can also cure many diseases, but again, it is not well endured by bottom fish.
Personally, I discovered a treatment, ESHA 2000, that treats more than 18 diseases. I tested it on a bearded titteya that had big red pimples on the body. The diagnosis was difficult. With this treatment, in 5 days it was like new !!! I also tested it on a goldfish of my grandmother very badly, he recovered in a few days.
Euthanize a fish
Unfortunately, in some desperate cases, there is only euthanasia left to relieve the fish. In this case, only one technique is painless and acceptable: the use of clove oil (available in large pharmacies-herbalists). Pour about twenty drops of clove oil into a small glass of water from the aquarium. The fish will then fall asleep and die peacefully. Attention, so that it dies, it is necessary that the dose is sufficient! Obviously, this method must be used as a last resort.
In any case, never scald the fish, throw it in the toilet or put it in the ice: all these techniques are barbaric and cause unnecessary suffering.