Diseases in aquariums affect all types of fish, including tetra fish. Aquariums that do not have sufficient water quality can cause many types of diseases in fish. Stress and dramatic changes in water and temperature can also cause a fish to have stress related diseases that can spread quickly to other fish in the tank.
Neon Tetra Disease (NTD)
Neon tetra disease affects tetras as well as various other species of aquarium fish. The loss of red in the neon's stripes and swimming difficulty are some of the first signs of neon tetra disease. This disease is sometimes confused with columnaris or mouth fungus rot.
Columnaris (Mouth Rot, Mouth Fungus)
Columnaris is a disease that affects the mouth, causing patches of grayish white thread like marks around the mouth. The fins will begin to deteriorate and the body will have sores on it. Columnaris is caused by a bacterium called Flavobacterium colmnare, also known as Flexibacter columnaris. Poor water quality in the aquarium is the main cause of the disease as well as any sudden change in the conditions of the tank.
Acidosis is a disease that is contracted within the aquarium environment. It occurs when there is a drastic drop in pH and puts the fish into shock. The fish may be gasping for air and struggling to breathe or may be hyperactive. The gills will soon start to turn red or brownish and slime will coat their bodies, cutting off even more oxygen soon causing death.
Gas Bubble Disease
Gas bubble disease is caused by a change in the aquarium's gas pressure. Changing out a large amount of water at one time or adding water that is much colder than the fish are accustomed to can cause this disease. The disease looks like blisters forming on the skin and fins of the fish. If the gas bubbles enter the bloodstream of the fish, it will kill it.
Bacterial Fin Rot Disease
Bacterial fin rot disease affects fish that are living in poor aquarium conditions. The fins become frayed and short due to the rotting and red sores appear in the areas affected by the bacteria.
Ich (Ichthyophthirius Multifiliis)
Ich is a disease that affects tetras and many other tropical fish. It produces white spots on the body, fins and gills of the fish that is infected with the disease. It is highly contagious and can spread quickly from one fish to another. If fish get ich and are not treated right away, it guarantees death of the fish. Loss of appetite and decreased activity along with white spots on its body are a few signs that the fish may have ich.