In my last time, fish die in an aquarium. Three have already died

I ask the answer to the question.

In my last time, fish die in an aquarium. Three have already died. First zebrafish. Eyes got out and scales began to rumble. Then a cockerel. Now two more two guppies. Boy and girl. What to do? Then I will add :)

Guppies became weak and died. Swam and died.

Perhaps tuberculosis (mycobacteriosis). It is with this disease that the fish may have buccal eyes (like your zebrafish "got out your eyes"), scaly hair, etc. The disease is infectious (and a large number of fish become infected), in the later stages it is not treated. From the Internet:

Heavily sick fish, other aquatic animals and plants are destroyed, the soil is boiled, the aquarium and equipment are disinfected with a 5% solution of bleach or 3% solution of chloramine. For disinfection, pour 1 liter of solution into the aquarium and thoroughly wipe the internal and external walls and corners several times a day with a cloth moistened in it. After this, the aquarium is rinsed several times, the soil is poured, and it is poured with fresh, settled water, plants are planted and after a few days the fish are launched.

Mycobacteriosis is a typical disease of a weakened organism, which was facilitated by poor fish conditions, such as poor sanitary conditions, overcrowding, poor filtration, and lack of oxygen. Therefore, the prevention of such diseases consists in creating impeccable, from the point of view of hygiene, conditions for keeping fish in the aquarium. The level of microbes in the aquarium should be as low as possible. To do this, you can use ultraviolet lighting, which kills part of the germs.

Important: These microbacterium can affect not only fish, but also humans. When working with an infected aquarium, you should be as careful as possible to avoid infection through the mouth (when the mouth sucks water through a hose), through wounds or abrasions on the hands. After microbacterium enter the wound site after an incubation period (3 weeks), papular skin changes begin in these places. Self-healing can occur after only 2 years. Therefore, you should immediately consult a dermatologist who will perform the treatment.

Before you have fish you need to know about the content in providing a life category of fish.