It may sound strange, but fish is also prone to colds. This happens usually because of too low water temperature. First signs of a cold-folded fins and black spots on the gills.
The only method of treatment in this case is ensuring the desired temperature, which must be not less than 23°. Please note that dramatically changing the water is not recommended. The temperature should increase only gradually.
In some cases the fish turn black due to a genetic predisposition. If the behavior does not change, the appetite is not lost, and the fish are active and mobile, then worry not.
Gill rot in fish
Gill rot is a very dangerous disease for aquarium fish. Water occupant may die within just several days. The main symptoms of such an infection are black bars on the body and in the head. The fish becomes very slow and floats up the tail. Externally, the impression that her body once again, thank you head.
The ailing fish should be sure to transplant from their neighbors. Gill rot is a contagious disease that can in a short time to destroy all the inhabitants of the aquarium. The optimal method of treatment is the copper sulfate solution that is added to water minimal dosages.
If the fish regularly move, the consequence could be their blackening. The main symptom of overfeeding is considered the sluggish behavior of water inhabitants and swollen tummies.
The most common cause black spots on aquarium fish is a disease called fin rot. Starts darkening of the body fish with the tips of the fins and tail.
Causes of fin rot are many. The most common of these are inappropriate conditions of detention, too many fish in the aquarium, a rare aquarium cleaning, strong water pollution.
To prevent fin rot it is necessary to regularly monitor the condition of the aquarium. Uneaten food in any case should not accumulate on the bottom. Otherwise, the water will become uninhabitable and will have a devastating effect on the fish.
Other causes of blackening fish
In rare cases, the cause of blackening fish can become larva kutikuly. The transmission is possible only in the case if, for example, turned to the aquarium fish representative of the river habitat.
Please note that some of the fish black spots appear gradually, but disease is not. A vivid example can be called a swordsman. Young fish have a more light color. Gradually the body black and colored dots appear.