Ich emergency treatment help

[ysrgrathe]

Hello,

After introducing a new fish into my pond, I had a confirmed (by a vet) case of Ich in my pond. Treatment was started on 6/10 consisting of 380mL of Parasite-S (37% formaldehyde). Treatment was repeated on 6/13 and 6/16 with water changes of 200G/day in between. By 6/18, fish behavior and appetite had returned to normal. Last night 6/23 (day 14 after first treatment), I observed one of my fish on the bottom of the pond, clamping. I have the vet coming back on 6/30 (earliest possible appointment). The vet is out of the country and cannot provide a recommendation.

My question: should I apply another formalin treatment now, or wait? Thank you for your advice.

Water parameters:
Ammonia: 0.1 mg/L (on 6/10, by vet's test) 0.0 mg/L (on 6/24, API drop test)
Nitrite: 0 mg/L
Nitrate: 12 mg/L
Salinity: 0
pH: 7.8 (+/- 0.3 daily fluctuation)
kH: >171 mg/L
Temp: 72F (on June 10th), 75F (on 6/24)

Other data:
Aeration: 120L/min
Size: 5000 gallons
Stocking density: 13 fish, from 13"-22"
Filtration: RDF => moving bed => ceramic media shower, ~7-8k GPH
Water change: 200G/day automatic

[ysrgrathe]

[fly4koi]

It looks there's some internal infection going on (dropsy), do you have a hospital tank or is salting an option?

[ysrgrathe]

I have a QT/hospital tank. But if it is ich, I assume it will affect every fish.

[fly4koi]

the treatment you did should've wiped them out, but whatever damages they have caused will take time to heal.

[SimonW]

Formalin can be used repeatedly without causing parasites developing resistance. I would do it again.

[RichToyBox]

The thing with ich is that it cannot be killed while it is embedded in the fish, or as an egg. It can only be killed as a free swimming tomite, on its way to a new host. So for using formalin type treatments, they need to be done almost daily for a couple of weeks, depending on temperature. I prefer salt at 0.3% or higher, up to 0.6% until the fish are symptom free of the parasites and then the salt can be removed during water changes. Salt will kill the tomites, and it is always there until diluted out of the pond, so it is more effective than the other trreatments.

[ysrgrathe]

Thanks all. I will treat again and then get further advice from the vet. I figured that due to temperature / lifecycle I might need additional rounds.