H2O2 and Ich

Hugh Mann · Oct 2, 2020

So I am back from vacation, and I have ich in my tank I have to deal with.

It's a pretty minor infestation, considering the only fish to show signs was a Hippo Tang. Not even the converted freshwater mollies have caught it. I'm getting my Hippo back from my lfs that treated it for me, so it's going into a clean tank while I deal with the ich.

The lfs recommends using hydrogen peroxide at 1ml per 50 gallons a day for a month and that should do it. Further reading tells me that h202 manages ich at best, not eradicates it. I'm sorely tempted to go management at this point, as I have tried and failed a couple times to eradicate it.

Anyone have experience with this method?
Does it actually work?
Is 1ml per 50 gallons the right dose?
How long should I keep it up?

Jay Hemdal · Oct 2, 2020

Hydrogen peroxide for ich is definitely "off label" use - I've been experimenting with it a bit, but don't have any active cases of ich to try it on. A couple of things I do know; you can measure residual H2O2 with a standard DPD chlorine test, any pink color, and there is an oxidant in the water (bleach, ozone or H2O2). In the case of accidental overdose, you can neutralize peroxide with a reducing agent, like aquarium dechlor.

Are you talking about using standard 3% drug store grade? If so, 1 ml per 50 gallons is way too low. I'm currently dosing a 16 gallon tank with 1 ml / gallon daily, working on controlling algae. Now, this tank has a lot of organics in it. Peroxide is quickly reduced by organics. If your tank is low in organics, it would need less peroxide and therein lies the problem - the dose is wholly dependant on factors that can't really be measured.

Most people who use peroxide for ich, do so as a dip, sometimes an adjunct to a FW dip, or sometimes peroxide in SW. Noga gives a dose for that as 10 ml of a 3% solution per liter of seawater as a 10-15 minute dip.

I could not find a published static bath (24 hour) dose in any of my references. I found an unreferenced dose for a "new aquarium" (having less organic material) of 1/3 of a ml per gallon.

Ultimately, you need a high enough concentration of the peroxide to oxidize the theronts. This is likely higher than the amount needed to oxidize your nitrifying bacteria - so don't blow out your biofilter!

Check this paper out: https://europepmc.org/article/med/21648246

It seems to show that you need >10 mg/l peroxide to control 85% of theronts - this works out to be about 60 ml of 3% in 50 gallons (if I did the math right!) . That seems a lot....

Jay

Tamberav · Oct 2, 2020

1ml at 50 gallons once per day? Absolutely not. I have an ich management tank and I am dosing 11ml 3 times a day (so 33 total a day) in about 70 gallons with a large UV (increases oxidation) and it has had no effect visibly on ich.

It has shown some promise on velvet when put on a doser with 2ml/hr over night to keep concentration up. I would guess that as peroxide dissipates, disease can continue to multiply in between hence needing to dose it more continuously.

najer · Oct 3, 2020

Firstly England calling, in the UK and Europe we tend not to have so many fish disease issues, I have never had a fish disease outbreak in 10 years of reefing and no I didn't touch wood as I am not superstitious.
I dose peroxide constantly at a slow rate using a Sochting Oxydator, don't ask me to explain the chemistry?!

I use 9% peroxide in my oxydators, 3% is very weak in vols.

Privateye · Oct 3, 2020

Just speculation, but do you think it could possibly have a slime production/sloughing component as well? Maybe not enough to shed trophonts, but to reduce theront attachment or something?

I'm a big fan of peroxide for various things, but I've never used it to target cryptocaryon. I often do a dip at the end of my acclimation for new fish. It can affect a lot of bacteria at the very least.

Hugh Mann · Oct 4, 2020

I did some more searching on the subject and found a dosing schedule starting at 1ml/10 gallons daily, building up to 1ml/5 gallons. Even that is only a management solution, not an eradication method.

So I think I am going to temporarily go management while I set up my new tank, and then hypo or TTM before transferring the fish to the new tank.

cbnspanky · Dec 18, 2022

najer said:
Firstly England calling, in the UK and Europe we tend not to have so many fish disease issues, I have never had a fish disease outbreak in 10 years of reefing and no I didn't touch wood as I am not superstitious.
I dose peroxide constantly at a slow rate using a Sochting Oxydator, don't ask me to explain the chemistry?!
I use 9% peroxide in my oxydators, 3% is very weak in vols.

I set up a new tank 2 months ago. It’s a 12 gallon long. I’d read about oxydators and decided to use one from day one. I cycled the tank with live sand, live rock and added bacteria. My clown fish did great. I’ve just added the biggest ich magnet I know, blue hippo, to the tank yesterday. I’m running the oxydator with 12% and have decided to do 1ml/5gallons 3% dosing 3 times a day for a month to test out several theories at once. I also did a 30 minute dip at 150ppm. So far the tang is happy and eating after 2 days. Fingers crossed.