Doc Johnson I have a fish disease problem I think you may be able to solve, if anyone can. 1X16 aquascape pond capacity 1500 gal. 2 years old..water condition good uv light 15 koi 3 Months ago these koi (from the patio side looking at them) we noticed these bumps(looked like pimples) on their tail fins..when taking them out of the water they seemed to be tiny blood spots and they also some had a few on their body. Treated with ProformC..they still have this..treating again with ProformC..no change. They are fine and frollick around the pond as usual. Have never showed no signs of illness, and still don't. PP doesn't help this either. Do you have a clue as to what this could be? I have a digital camera if you want a pic, I could possibly put one in a cooler and snap it. they are large 14" 5 are Japanese, although 1 Japanese lost it's color, over winter. Harvey W Smith Shreveport LA 71118

Harvey W smith

Honestly it sounds like you're describing broken rays in the fins. Individual rays in the fins and tail can be broken, and what you see there will be a white, very tiny 'knuckle' in the ray - and if three or four rays are broken at a time, these tiny white knuckles will line up in a row. Of course they can have blood in the "pimple" - as the ray is broken and there will be some healing process.

Of course, it could also be anchor worm but you did not report that there were fine threadlike worms protruding from these white pimples.

If you would like to upload an image, please do, it will help with the diagnosis:http://www.erikjohnson.com/uploads

Thank you for your consideration.

Dr. Erik Johnson