- Lethargy: The fish may be less active than usual, hanging around the bottom of the tank or staying in one place for long periods.
- Loss of appetite: The fish may stop eating or eat very little.
- Discolored gills: The gills may be pale, red, or brown instead of the normal bright red color.
- Cloudy eyes: The eyes may be cloudy or milky, and the pupils may be dilated.
- Skin lesions: The fish may have sores, ulcers, or other skin problems.
- Rapid breathing: The fish may be breathing rapidly or gasping for air.
- Abnormal swimming behavior: The fish may swim in a jerky, uncoordinated manner, or it may swim sideways or upside down.
- Floating: The fish may float at the surface of the water or sink to the bottom.
If you see any of these signs, it is important to take action immediately. Check the water quality and make sure the tank is clean and free of toxins. You may also need to treat the fish for a bacterial or fungal infection. If you are not sure what to do, contact your veterinarian or a qualified aquarium specialist.