Why are my koi and goldfish flashing or rubbing on the tank bottom?

Thanks for reaching out about your aquarium and including photos. Did you test your water quality prior to the water change? Continue to test for pH, ammonia, nitrites and nitrates. Pristine water quality is needed for health. Are any of the fish new, that could have introduced parasites? Itching/flashing can be due to water quality, external parasites, bacterial or viral infections and other causes. The white lesions on the photo could be fungal infections. A skin scrape and examination under the microscope (at a veterinarian's office) is needed for an attempt to determine a cause. Fungal infections are often secondary problems, so check water quality first. Good luck.

Check water chemistry first. 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 ( 0 ppm) of ammonia and nitrites with nitrates at 20 ppm or less. Perform partial water changes, no more than 30% at a time, to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock. Check water temp as well. Any of these can drive a fish to the surface. The "flashing" (darting about) can be due to infection (bacterial, fungal or parasites). Consider a broad spectrum antibiotic or an "all in one" product to treat multiple infections. Look in the Aquarium section of the local Petco for options. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.

Consider a broad spectrum treatment such as General Cure by API or Parasite Clear by Jungle Labs. Follow label directions. Plain aquarium salt (NOT table salt) can be used concurrently to aid in healing and to treat minor infection and fin rot. Dissolve up to one tablespoon per gallon of water into a cup of tank water and gently pour it into the tank. Test water chemistry using a home test kit or submitting a water sample. Most pet or fish stores will do this for free or for a nominal fee. Correct any imbalances using aged or conditioned water that is temperature matched to prevent further stress or shock. Use a conditioner such as StressCoat as well. Confirm adequate filtration to maintain water quality.

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.

It certainly sounds like something is irritating this fish. Most often it is caused by parasites, usually ich. With ich you sometimes see salt like spots on the fins, you also may see a dusting in the dark if you shine a light. Other things that could cause itching would be irritants such as high ammonia levels. Personally I do not like adding chemicals to the water, especially not with other species such as snails and shrimp. To treat ich you can simply increase the water temperature and you can bathe the individual in salty water.

This could be bacterial or parasitic infection. It is difficult to determine definitively since the image provided is not clear. Fish can be difficult to photograph. Basic care includes checking water quality and chemistry. This can be done using a home test kit or by submitting a water sample for testing. The local Petco may do this for free or for a small fee. There should be an absence of ammonia and nitrites with nitrates at 20-60 ppm. pH should be as close to 7 as possible, avoiding large swings. Koi can tolerate a wide range in temperature, but generally do best between 65 F and 75 F. Again, avoid large swings in temperature to prevent stress or shock. If necessary, a partial water change can be done to stabilize chemistry and/or improve water quality. If you have other koi, consider placing this one in a hospital tank to make treatment easier and to prevent spread if the condition is infectious. Plain aquarium salt (NOT table or Epsom salt) can be used to reduce stress, improve gill function, treat minor infection and aid in recovery. Dissolve 1 tablespoon per 5 gallons of water in a cup or two of tank water and gently pour it into the tank. Treat for 14 days then reassess the condition. If there is no change, consider a broad spectrum antibiotic or "all in one" treatment. Either can be found in the Aquarium section at Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated. All that said, if the spots multiply and appear like tiny grains of salt, it could be an ich infection. In this case the entire tank will require treatment. There are several commercial ich medications that can be used. You will also need to thoroughly vacuum the substrate/gravel in the tank and wipe down all tank furniture.

This could be ammonia burn. Check the water chemistry. 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 (0 ppm) of ammonia and nitrites with a nitrate level of 20 ppm or less. Partial water changes will be needed to stabilize chemistry. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. Goldfish are cold water fish and do best between 65 F and 72 F. When using an ammonia reducing product, be sure to test the water after treatment but before pouring the treated water into the tank.