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My fish has a red spot. What does this mean and should I be concerned?

Updated On September 23rd, 2025

Hi here, I’m really worried about my fish. He has this red spot and I don’t know if it’s something to be concerned about

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Answered By Todd Cecil

Veterinarian

Published on December 9th, 2018

Thanks for reaching out about your fish and including a photo. This is a fairly large lesion and needs to be diagnosed and treated. Parasitic infestations and bacterial infections must be considered. Adding non-iodized salt at 1 tablespoon per 5 gallons for 3 consecutive days might provide some osmotic relief but is not therapeutic levels. A skin scrape and microscopic examination is needed to diagnose parasites is needed. Different parasites require different medications. Bacterial infections should be treated with systemic antibiotics through injections or oral medications, not water additives. Good luck.

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