My goldfish showed signs of finrot so I treated her with antibiotics for a week as per instructions on the bottle. She seemed to be better. However, today I looked at her again and one of her fins on the side is half gone. She is in a tank with 3 other male goldfish. Was it bitten off? Is it fin rot?

The second weird part is her scales. She is completely orange but the same side that has the bad fin is going white. Some of the scales are sticking out. I'm not sure if it's dropsy or what is going on! Help!

This is an ammendment to my previous post. I looked at my fish outside the tank and the scales aren't white. THey are missing. It really looks like one of my other fish took a huge chunk out of her, including that fin. What do I do about biting fish? And how do I help my injured fish heal??

Hi Rambo, welcome to koko's!

Unfortunately, GF have a way of telling what one of their tankmate is not feeling the best or is weak. They can be merciless.

How big is the fish? Isolation is the best option.

She is about 3-3.5 inches long. I put her in a separate tank with antibiotics to prevent bacterial infection. Anything I definitely should or should not do?

Rambo

You should provide the best water quality you can. I hope you have a filter, aeration and maybe a heater for the hospital tank. What is the temp of the tank?

If the wound is serious, you might want to swab it with iodine, making sure that none gets into her eyes, gills and mouth. Only do that once.

If it is finrot, a salt bath might help.

There are different dosages depending on the severity of the problem. With my one koi, her fins turn red sometimes. I just do a light salt treatment and she's fine again. Never had to treat finrot in the tank though...