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My goldfish has a red spot. Is it red patch disease? How to treat?

Updated On September 23rd, 2025

Pet's info: Fish | Gold Fish | Male | 3 months and 17 days old

This red spot is getting worse ive monitored the ph and ammonia is it red patch disease what should i do? Treatments!?

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2 Answers

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Answered By Todd Cecil

Veterinarian

Published on December 28th, 2019

Thanks for reaching out about your fish. Red spot disease is a fungal infection and usually appear fluffy. Adding anti-fungal medication to the tank is not recommended as these can often cause more problems. A veterinary visit is recommended to assess. If you only have goldfish, no live plants, no invertebrates, you can try adding aquariums salt (not table salt) to the tank at 1 Tablespoon per 5 gallons, once daily for 3 consecutive days to slowly raise the salt concentration. Monitor appetite. If fish seem stressed, perform a partial water change. Good luck.

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    Answered By Angel Alvarado, LVT

    Licensed Veterinary Technician

    Published on January 14th, 2017

    You should separate the affected fish out into a smaller hospital tank for ease of treatment and to prevent spread. Monitor the remaining fish for symptoms. A wide variety of minor infections (bacterial, fungal and parasites) can be effectively treated using simple aquarium salt. Dissolve one teaspoon of aquarium salt (NOT table salt) per gallon of water in the hospital tank. Perform daily water changes, replacing any water with salt in the same dilution. Do not simply continue to add salt to the tank. Treat for 7-10 days. You should see improvement or resolution within this time frame. If not, you may need antibiotics or antifungals. These can be purchased at most pet stores. Do not return the fish to the home tank until all symptoms have resolved. You will need to reevaluate your tank space with that many goldfish. For fancy goldfish (double tails), the general stocking rule of thumb is 20 gallons for the first fish, then 10 gallons for each additional fish. This amount can double for single tail goldfish. The reason being they create large amounts of ammonia which can be deadly in high enough concentrations. Overfeeding and dead plant material can compound the problem. Powerful filtration, careful monitoring and avoiding overcrowding are all keys to keeping goldfish.

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