My fish has a bump on its head. Is it serious? What should I do?

Hi and thanks for your request and pictures. This tumor like lesion could be due to a lymphocystis. This is a virus (herpes), mostly seen in goldfish, which can cause these type of cauliflowers mass-like lesions. Of course to be confirmed, this should be sampled and or removed completely. Unfortunately these masses can grow much bigger that the one showed in the pics and can become infected. A clinical examination at your local veterinarian is essential to confirm these clinical suspicions and treat appropriately. 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. If this answer was helpful please let us know, this will be used to improve our service!

Without an image or exam, it is difficult to say with any certainty what the lump may be. Infection or injury would be likely culprits. If he has anything sharp in his bowl, remove it. Check the water quality and chemistry as poor water quality can predispose him to infection. Use a home test kit or submit a water sample for testing. Most pet stores will do this for free or for a small fee. Aim for 0 ppm ammonia and nitrites with a nitrate level of 20 ppm or less. Partial water changes can be done to stabilize chemistry and improve water quality. Use only aged or conditioned water that is temperature matched to prevent stress or shock. Bettas do best between 78 F and 80 F. Change no more than 30% total volume at one time. You can try using plain aquarium salt (NOT table or Epsom salt) as a general tonic. It can treat minor infection and helps aid in recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then reassess his condition. Perform water changes afterwards to reduce salinity. Do not use salt for more than 14 days in a row. If there is no change, a broad spectrum antibiotic can be found in the Aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.

Thanks for reaching out about Spike and including a photo. It is difficult to visualized the lump on the picture but if water quality is pristine, a veterinary visit might be in order to assess. Bumps/lumps can be parasites, infections, enlarged internal organs and more. Monitor appetite. Containers of food should be re-purchased every -23 months as vitamin C degrades quickly and fish has a nutritional requirement for vitamin C. If not a new fish (owned for several months or more), unlikely to be parasitic problem. Good luck.

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.

Thank you for your question, and thanks for the pictures - they are very helpful! Unfortunately, there are many things that can result in white ares on the skin of fish. As you mentioned, Ich is one of them, and this is a type of parasite. There are other parasites that cause white areas, and there are also types of bacteria, viruses, and fungi that can cause them too. In addition to this, it may be tissue, as you mentioned above as well - this tissue would be abnormal, and may be benign or malignant in nature. Due to this, it would be ideal to have Curly seen by a veterinarian. Your veterinarian can take a sample of the white areas and can evaluate the material under the microscope. This will help to guide what type of treatment would be needed for Curly (example: antibiotics, anti-parasitics, anti-fungals). I hope that gives you a place to start, and I hope that Curly feels better soon!

It may be a tumor or infection since it is just on one side. Without diagnostics though, it can be difficult to determine the underlying cause. Maintain pristine water quality via filtration and regular partial water changes. You can try a broad spectrum antibiotic which can be found in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated. If antibiotics to not resolve the lump, then it could be a tumor or mass which would need to be addressed by a veterinarian experienced in treating aquatics.

Maintain pristine water quality via filtration and regular partial water changes. This is the cornerstone for treatment and recovery. Plain aquarium salt (NOT table or Epsom salt) can be used as a general tonic to reduce stress, improve gill function, treat minor infection and aid in recovery. Dissolve 1 teaspoon of salt per gallon 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 necessary, a broad spectrum antibiotic can be used concurrently. Find one in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.