Why is my koi fish floating upside down in the pond and then recovers?

Check the water quality and temperature. Warm water will not hold as much oxygen as cool water and goldfish are cold water fish. Ideal water temp is about 21 C. Use a home water test kit to check parameters. Ammonia and nitrites should read 0ppm (parts per million) and nitrates can be 40ppm or less. If you don't have a test kit, most pet stores or aquarists will test a sample for free or for a nominal fee. Ensure adequate filtration and oxygenation. Use a filter that will comfortably handle twice the volume of your tank. An airstone will increase oxygenation. A tank hood or cover is recommended to prevent fish from jumping out.

Since the others in the tank are behaving normally, this one may be sick or injured. Ideally, it should be separated into a quarantine or hospital tank Check water chemistry first, even if you've done it already. You can use a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0ppm) of ammonia and nitrites, with nitrates at 20ppm or less. Perform partial water changes to correct or stabilize water chemistry. Use only conditioned water that is temperature matched to prevent additional stress or shock. Goldfish are cold water fish and do best between 68F and 74F. Change no more than 30% of the volume at one time. In the absence of other symptoms or injury, medications cannot be recommended. You can use plain aquarium salt (NOT table or Kosher salt) as a general tonic to decrease stress, increase gill function and aid in recovery. Dissolve 1 tablespoon of salt per 2 gallons of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then perform partial water changes to decrease salinity.

Goldfish sit at the bottom of a tank when they are not well, often because toxins have built up in the water. Goldfish are usually active, and lethargy is a sign of illness. Maintaining good water quality is essential for proper aquarium care. In the enclosed, finite space of a fish tank, toxic elements, such as ammonia and nitrates, can build up in the water causing disease and killing fish. The only way to detect and control toxins is to perform regular chemical tests on the water and to perform gradual water changes to remove impurities and maintain the proper water parameters.

If you are feeding flakes, the fish may be swallowing air while feeding. This may account for the signs you are seeing. After a period of time, the fish may expel the air and right themselves. Try feeding a pelleted or stick diet that sinks to prevent gulping air at mealtimes.

Usually lack of water quality, lack of oxygen, overcrowding and abnormal temperature are all common causes of this behaviour. They could be hungry as well, but usually they come to the surface at certain time or in response to visual stimuli like your presence. Begin by submitting a water sample for quality testing. Most pet stores will do this for free or a nominal fee. Clinical examination should always include a water quality check, even if you have done so already. Water testing should be performed with a quality test kit, measuring NH4, NO2 and NO3. High ammonia levels, PH imbalances may be responsible for these signs. Oxygen concentration and quality of the filters should be determined as well. If water quality is good and there are no major imbalances, your fish should get examined to look for any sign of bacterial/fungal infection and eventually water should be treated. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.

Thanks for reaching out about Kirky and including a photo, although the photo is out of focus. Swimming to the surface and gulping air is typically and indication of gill disease. Gill disease can be caused by poor water quality, bacterial infections, gill parasites, and metabolic disorders. First, check water quality for pH, ammonia, nitrites and nitrates. Correct problems. Make sure to treat tap water for several hours prior to adding to the tank. If water quality is correct, a veterinary visit for assistance in a diagnostic/treatment plan. A gill clip can be examined under the microscope to determine parasitic or other gill disease. Antibiotics added to the water typically cause more problems than benefit, altering biological filtration. Good luck.

Occasional flashing can be normal. If it is frequent, check water chemistry first. Elevated ammonia levels can irritate or "burn" the gills. Sudden changes in pH can also result in increased flashing. Partial water changes using aged or conditioned water that is temperature matched can resolve imbalances in chemistry. Exam the gills closely for evidence of gill flukes, another parasite that can cause irritation and flashing. Gills may be inflamed or have mucous on them when gill flukes are present. You won't see them though, they are microscopic. Heavy breathing is also a symptom. Treatment is with praziquantel which you can find in the aquarium section of the local Petco.