Help diagnosing fish
Six fish have died in the past three weeks, and we are looking for help diagnosing the issue. We are thinking it may be flukes and dosed the pond today with PraziPro. The fish initially did respond like it was working (minor agitation, briefly rubbing/flashing) and appear more active, so we’re hopeful that things are on the upswing… They’re currently relaxing in or near the shallower end like they usually sun.
POND INFO
We have a roughly 1200 gallon backyard pond that has been established for four years. It has a 2,000 gallon pump with a UV filter as well as a waterfall and bubbler. We also have an air stone running in the shallow end temporarily. Water has tested within normal parameters the entire time, using the API Pond Master Test Kit.
FISH INFO
Right now there are 11 fish—five koi and six goldfish—but six small fish have died over the past three weeks. The pond was slightly overstocked and it has been almost exclusively the newer fish (4-5”, acquired in April) who have died. The two biggest koi are about five years old and have showed no symptoms, and neither have the more mature goldfish.
SYMPTOMS
About half of the fish who died showed no symptoms. The other half were lethargic with quick respiration, hanging out near the surface or in the shallow end (<6” deep) and occasionally blowing bubbles at the top, but were not gasping for air or flashing. The deaths occurred within 8-24 hours of symptoms first appearing. I did not note anything unusual about the gills, body, scales, etc. on the decedents. No redness, swelling, sores, film, cuts, etc. In hindsight with reading more about flukes, their gills may have been slightly pale?