My molly fish has a white dot on its tail. What should I do?

Although a picture of it would be essential to determine the underlying cause, this could be caused by fin rot. Fin rot is commonly caused by poor water quality. If he/she is in a tank larger than 2 gallons move him/her to a smaller tank if possible to make treatment easier. The best treatments for mild fin rot are frequent water changes and aquarium salt. Maintain the water the treatment tank between 76-78'F. Turn the light and filter off for the time being. Aquarium salt can be used at 1 teaspoon per gallon. Dissolve it in tank water before adding it. Perform daily 100% water changes, making a fresh salt solution each day. Treat for a maximum of 10 days.

It could be early ich (white spot) infection or another infection (bacterial or fungal). To be safe, separate him into a quarantine tank and monitor for any change. You can treat for ich as you did it in the past if indicated. Bacterial and fungal infections have different treatments, so I would be hesitant to recommend a specific medication without more information or a definitive diagnosis. You can use plain aquarium salt (NOT table salt or Epsom salt). As a general tonic to reduce stress, increase gill function, treat minor infection of many types and to aid in recovery. This can be added to the quarantine tank at 1 teaspoon per gallon of water. Treat for 10-14 days then reassess the condition.

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.

The natural antibiotic properties of Melafix work best with minor or external infections. Your Molly may be quite ill and may need more aggressive treatment. If you have other fish in the tank, especially Bettas or Gouramis, you cannot use Melafix as this could harm them. Separate the molly to a hospital tank and treat there. You will need to remove the carbon filter insert during treatment or it will filter out the Melafix. The symptoms listed may indicate bacterial infection, parasites, constipation or obstruction. If Negrito has a pinecone appearance, he may have a serious infection (dropsy) that is causing kidney failure. This would in turn cause the swollen abdomen and lack of appetite. Check the water chemistry, temperature and filtration. Ammonia and nitrites should be absent and nitrates can be present at 40ppm (parts per million) or less. Molies do best in water between 75F and 80F. Perform a partial water change if necessary to stabilize chemistry and maintain water quality. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. Clean water is the best way to manage any infection. Plain aquarium salt (NOT table salt) can be used at 1 teaspoon per gallon of water but it is not recommended if your molly has dropsy. In this case, Epsom salt can be used to decrease swelling. Allow a 15-30 minute swim in a bath prepared with 1 tablespoon of Epsom salt per gallon of water. Do this in a separate container. It could help with constipation as well. If the Melafix does not help, use a product such as Kanaplex or Maracyn. These are broad spectrum antibiotics that you can find in the aquarium section of the local pet or fish store. Follow label directions carefully and remove the carbon filter insert during treatment if indicated. Hopefully, any infection will be resolved with treatment. If it is dropsy, unfortunately, this condition has a high mortality rate.

Black spots or discoloration can be caused by elevated ammonia levels. Test water chemistry using a home test kit or submit a water sample for testing. Most pet or fish stores will do this for free or for a nominal fee. Ammonia and nitrites should be 0.25 ppm (parts per million) or less, nitrates can be 40ppm or less. Partial water chnages daily should be done to decrease ammonia levels. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. Elevated ammonia levels can be caused by overfeeding, new tank syndrome or overstocking.

In this case you need a quite radical approach. 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. If this answer was helpful please let us know, this will be used to improve our service!

The tiny spots could be a parasite infection. Ich presents as small dots similar to grains of salt. It will quickly overrun a tank and can kill fish if left untreated. You will need to treat the entire tank as opposed to just affected fish. A broad spectrum parasite medication that covers ich can be purchased at the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.