Why are my Dojo Loach's eyes swollen? Is it popeye and how to treat?

It could be "pop eye". This can be caused by infection or trauma (aggression or from tank furniture). Treatment will include medication and maintaining pristine water quality. Goldfish produce a larger than average bio load (wastes) which can quickly overwhelm a tank and filter. Ideally, one goldfish should have 20 gallons of water and 10 additional gallons should be added per extra fish. The filter should be rated for at least twice the volume of the tank. Check water chemistry using a home test kit or by submitting 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 maintain water quality. Use only aged or conditioned water that is temperature matched to prevent stress or shock. Goldfish are cold water fish and do best between 65F and 72F. A broad spectrum antibiotic can be found in the Aquarium section of the local Petco. These include erythromycin, tetracycline or kanamycin. Brands include Kanaplex, Maracyn , FishMox or FishCillin. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.

Popeye is a symptom of an underlying disorder in the tank. It can be a result of trauma or infection. Most cases can be managed by maintaining water quality and a broad spectrum antibiotic. Quarantining as you have done is always a good move. Check the tank for any furniture/décor that may cause injury. Check the water chemistry, filtration and temperature next. Any imbalances can predispose a fish to illness. Partial water changes can be done to improve quality and correct imbalances. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. Maracyn Plus or Kanaplex can be found in the aquarium section of the local Petco or fish store. You can use either, in addition to plain aquarium salt (NOT table salt), to treat. 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 with salt then perform partial water changes to decrease salinity. Treat only the amount of water going back into the tank with salt to avoid overdosing.

'Popeye' syndrome can have different causes including infections and poor water quality. In your case the other eye may be become affected very quickly. Begin by submitting a water sample for quality testing. Most pet stores will do this for free or a nominal fee. High ammonia levels, PH imbalances may be responsible for that. Oxygen concentration (this could be one of the main causes as excess of O2 can cause it very commonly) 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.

Separate him out to a separate tank or bowl. This will make treatment easier and may prevent spread to other fish. Pop eye is typically due to a bacterial infection. This can be due to poor water quality, stress or possibly introduced by new additions. You can use Melafix, Maracyn or Maracyn II to treat. Either can be purchased in most pet stores or online. Follow package directions. Keep the water in the hospital tank clean. Use treated or aged water for water changes. A protectant such as StressCoat can be added as well.

Thanks for reaching out about your fish and including photos. Don't think it ruptured as these usually collapse. Corneal bleeding can be due to trauma or ruptured blood vessels from disease. Check and correct water quality. A veterinary visit is recommended to assess and establish a diagnostic/treatment plan. Good luck.

It may be a bacterial infection or trauma. Monitor for bullying since you have other fish. Most minor infections can be managed or resolved by maintaining pristine water quality. A bit of plain aquarium salt (NOT table or Epsom salt) can be used as a general tonic to aid in recovery, reduce stress and improve gill function. 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 10-14 days then reassess the condition. If the condition is unchanged, consider a broad spectrum antibiotic. You can find one 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 your goldfish. Kanaplex has an antibiotic called kanamycin and is not absorbed systemically even if ingested, and fresh water fish do not drink water. The best treatment for popeye are systemic antibiotics (injections) and a carbonic anhydrase added to the water. A veterinary visit is highly recommended to assist with a diagnostic/treatment plan. Good luck.