My goldfish is 3 years old and kind of stupid (like owner like pet ). Anywho, a few days ago, it had these red blotches all over its top fin, and now they're gone. I probabaly shouldn't be worried since it's gone, but I want to know what is wrong,can it happen again, and is it fatal?
dragonfly_sg
Favorite Answer
Best advise I would give is for you to do a 50% water change and continue to monitor.
I suspect the water quality is not really in tip top condition but your fish seem to be healthy enough to be able to resist whatever bacterial your water could throw at it :) So to help your goldfish, you would probably want to improve the water quality by doing a 50% water change once a week for the next two weeks.
Zoe
Goldfish aren't renowned for their genius and wisdom ;) lol
Sounds like finrot or irritation caused by something in the water. Long finned fish tend to get it much more easily than small-finned fish. Check your nitrites and ammonia - both should be at 0. If they're any higher, increase the frequency of your water changes, add some salt to the water (about 1 tsp per 5 gallons) and possibly look into getting a larger tank / more filtration.
And nope, not fatal, unless you let it get worse and worse and don't do anything about it :)