What are the red streaks that sometimes show up in fins? I can't find any info on them, I don't even know what they're called. Can somebody give me some general info on them? Thanks.

I'm not sure about the "Sometimes" part, but red streaks may be an indication of infection, or they may just be natural color changes. To know more, you should answer the questions in the white box at the top of the page - sometimes water quality problems or other stressors can cause the fish to exhibit symptoms that would normally be associated with illness.

My inclination is that if your water quality is good and there are no other stressors you should treat the fish for the possible infection, since it's much more likely that you will be able to cure it if you start medicating while it is in its earliest stages, but others with more experience may have better advice for you.

The reason I did not answer those questions is because it is not my fish who have the problem. I am just looking for general information on something I have seen before in fish.

Red Streaks are normally called red streaks.They are caused by a number of reasons-poor water quality/stress/illness/parasites,bacterial infection,etc.Sometimes white goldfish have a tendency to show these more than others.It's really hard to give you any general information.The only thing that I can really tell you is that it's not normal for fish to sport them,and if they do,there's definately an issue going on. And when someone does see them,they should start with checking their water quality first.

Hmm ok that makes sense. Does anyone know of the names of any particular parasites and/or bacteria that can cause red streaks? Sorry not trying to nitpick, I'm just really curious about them, info on them have always been obscure to me. Thanks for that info Devs!

Ive seen it mostly with stressed fish ie. moving them to a different tank ect. Also sometimes when they get ich this happens but because the fish are stressed out.