My molly fish's tail is turning clear. Is it fin rot? How do I fix it?
Updated On September 23rd, 2025
My molly fish’s tail is starting to turn from black to transparent...is there anything wrong with it
3 Answers
Most Helpful Answer
Published on August 15th, 2019
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.
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Related Answers from Veterinarians
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Published on September 21st, 2018
Maintain pristine water quality regardless of any other treatment. Clean water is the foundation for treatment and recovery. You can use aquarium salt, but no more for 14 days. An anti fungal medication may work *if* the condition is fungal. If it is bacterial, it won't help. You can try an 'all in one' product, such as Lifeguard (by Tetra). Find it in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.
1Pet Parents found this answer helpful
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Published on May 12th, 2020
Thanks for reaching out about Tony and including photos. First, test water quality for pH, ammonia, nitrites and nitrates, as poor quality is often a primary cause of fin rot. Betafix and Melafix rarely improve things, so are not recommended until a diagnosis can be made. If water quality is correct, review diet as vitamin C deficiencies can also cause similar problems. Food pellets should be replaced every 3 months. Good luck.
1Pet Parents found this answer helpful
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