I have two butterfly koi which have been displaying discolored fins. This has been going on for about a year, without getting better or worse. There is a lot to unpack here so I'm going to try to list out as much as I can think of as simply as possible.
Symptoms:
- Symptoms on two butterfly fish. Other fish asymptomatic.
- All fins showing as opaque instead of clear, with pink blotches, red streaks, and ragged (especially tail).
- One of the two fish breaches fairly regularly.
- No flashing observed.
- The fish will sometimes rest on the bottom during the day, but not all the time/all day.
- Still eating normally and for the most part acting normal aside from what was specifically mentioned.
- These fish have been scraped & scoped by a veterinarian who did not find any parasites.
- Symptoms have been static for almost 1 year (never better or worse).
Water Parameters:
Ammonia: 0
Nitrite: 0
Nitrate: 10
pH: 7.4 - 8.0 depending on season, but not swinging more than 0.1 per day when spot checked.
KH: Keeping this around 5 with the addition of baking soda, and recently added crushed coral to S/G filters. Without baking soda this will drop to near zero.
Pond Information:
- 2500 gallons (confirmed)
- Bottom drain & skimmer to zakki seive & 2 S/G barrels (4500 GPH)
- 55 w UV
- Plenty of aeration with BD & waterfall
- Mostly fed JPD
- 8 koi (3 large, the rest smaller - all of the smaller are new in the last year - more detail below).
Relevant Timeline:
- I have had the fish in question in the current pond for 2.5 years, but 7 years total
- Last spring I added new fish for the first time. They brought in some kind of parasite which killed one of my established fish and two of the new fish (This brought me from 4 large koi to 3 large and one small). I was not able to scope and ID but I treated with 2 separate treatments of 4-day FMG (BSDT), 2 treatments of Prazi, and one of flubendazole. That seemed to take care of the acute parasite issue, but that is when the fin issues started and never fully resolved.
- Last year I tried 2 weeks of medicated antibiotic food later in the season to fix the fin issue.
- Last year added two more small fish, one in summer, one in fall, bringing me to 3 large and 3 small.
- Last year I upgraded filtration from 1 S/G to 2 S/G.
- This spring I had a vet come out and scrape/scope the fish to determine if there were residual parasites from last year which were continuing to cause the stress leading to fin issues. No parasites found.
- 2 weeks ago added 2 more small fish bringing me to 3 large, 5 small.
So I am looking for next steps/options. The options I have come up with are below, but if there are other options I'm open to hearing those as well.
1. No medical intervention. Continue to give them clean water, good food, minimize stress, and let them recover.
2. Treat the pond with something like PP (perhaps a specific multi-treatment regimen).
3. Remove the fish to hospital tank and either treat with waterborne antibiotic and/or re-try use of medicated food. If this is the strategy, I need some help determining specific treatment.