Hi-
I have a fish with a bacterial infection/septicemia. I am taking as many steps as I can to help him fight the infection (quarantine, aeration, salted water, PRISTINE water, antibiotics in the water, antibiotics in food).
I think he IS improving. he had slight dropsy which is gone, he is eating (which he wasn't doing for a while), and he is active.

HOWEVER, the red streaks in his tail fins have not gone away. I can find very little info on septicemia (I have looked). My question: Considering I am doing quite a lot to get him healthy (and dealing with all water parameters) HOW LONG UNTIL THE RED STREAKS GO AWAY?

When they go away, is that a sign that he is finally healthy? I would like to reintroduce him to my main tank, but the streaks make me suspect he is still ill. he has been in quarantine for about a week.

please let me know, or at least direct me to where i can find info on the time frame of septicemia--i have looked. there is a dearth of it.

THANK YOU.
alexis

Likely, you're okay at this point as soon as the fish starts eating again. What happens is that the quarantines are usually too small, (under five hundred gallons) and the fish experience stress) from this and the fins get injected. Nitrates could also be high in quarantine. If the external wounds are healing, and the fish will take food, especially a prophylactic medicated food like MediKoi - then you will do better returning the fish to the main pond (assuming it's similar in climate to the quarantine) so he can stretch out and rejoin his clan.
You'd be surprised how many folks simply "overdo it" and keep fish in the hospital too long. Mark my words, as soon as you or your Koi feel better, good enough to go home - DO IT! :)
Doc Johnson
To answer your question: Septicemia kills the fish within the week unless treated. Dilated blood vessles in the caudal fin of large fish is normal, especially when unhappily confined or indoors. Nitrates also cause dilation of caudal fin vessels.