Question
I had a new larger pond built about 2 months ago. I moved about 25 Koi into the new pond, leaving about 10 Shubunkin in the original pond which is a 7 ft diameter round in ground pond. The new pond is 15ftx7ftx4ft. The Koi have been very shy about coming up so I have not been able to get a good look at them, but tonight I noticed the shubunkin have a bad case of fungus going on. The first I noticed was one with a bad fungus around the mouth, then was able to spot other areas on the other fish. I am devestated, I have never had fungus in my pond and had ich only one other time. I am sure the moving of the Koi has stressed every one, I know it stressed me, but these guys did not even get moved. But catching the Koi was interesting to say the least, so the shubunkin were involved. The 2 ponds are connected via stream so I am sure I need to treat the whole thing, although I can seperate the two ponds by shutting off the stream water and run them independently. I had some ich rx containing formalin so I used it tonight. What is the best method of treating the problem safely? I have plants in abundance, but I do keep a bit of salinity in the pond, (about 1 cup per 100 gallons) I can't stand to lose my wet babies! Help!

Answer
Your old pond was at most 288 gallons while your new pond is at most 3150 gallons.  Koi experts say to have 1000 gallons for the first koi and at least 100 gallons for each additional koi so your pond is close if not over (eventually) capacity.

When koi or goldfish are put into a new pond, it is normal for them to become shy and skittish as it's a new situation.

It's strange that the unmoved fish would be the ones to become sick.  I suggest adding pond salt (0.01%), PimaFix by Aquarium Pharmaceuticals, and maybe even an actual fungal medication.  They are pretty strong and may harm or kill other animals (tadpoles, snails, insects, etc.).  Plants don't like salt so you may want to keep the salinity below 0.05%.  They sell salt test kits for ponds.  See
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=5362&cm_mmc=Affili...

Formalin may help with parasites but probably not fungus.

I hope the fish improve!

Robyn
fishpondinfo.com