There are several common fish diseases that can affect aquarium fish. Here are some of the most common ones and their treatments:
Ich (Ichthyophthirius multifiliis): Ich is a parasite that causes white spots to appear on the fish's body, fins, and gills. It's highly contagious and can be treated with medications containing formalin, copper, or malachite green.
Fin rot (Pseudomonas or Aeromonas bacteria): Fin rot causes the fins and tail of the fish to deteriorate, and can be caused by poor water quality or injuries. It can be treated by improving water quality, removing any damaged tissue, and administering antibiotics.
Swim bladder disease: Swim bladder disease causes the fish to have difficulty swimming and maintain their balance. It can be caused by overfeeding, constipation, or bacterial infection. Treatment may involve adjusting the fish's diet, increasing water temperature, or administering antibiotics.
Dropsy (Edwardsiella bacteria): Dropsy is a bacterial infection that causes the fish to develop swollen, bloated bodies and protruding scales. It can be treated with antibiotics and improved water quality.
Velvet (Oodinium): Velvet is a parasite that causes a yellow or brownish coating to appear on the fish's body. It can be treated with medications containing copper or formalin.
Columnaris (Flavobacterium columnare): Columnaris is a bacterial infection that causes white or grey patches on the fish's body, fins, and mouth. It can be treated with antibiotics and improved water quality.
Treatment for fish diseases often involves a combination of improving water quality, administering medications, and adjusting the fish's diet. It's important to follow the instructions on any medications carefully, and to quarantine sick fish in a separate tank to prevent the spread of disease to other fish in the aquarium. Additionally, it's important to regularly monitor and maintain the water quality in your aquarium to prevent the occurrence of disease in the first place.