Hydrogen peroxide, fish deaths, what causes it

[adhdan]

Im battling diatoms and algae in my planted tank, its around 5month old so i maybe should of just left it, but i gave a single dose of hydrogen peroxide, i dosed around 2.5ml 3% per US gallon of water, turned my filter off, left the powerheads on, left it for about 2 hours then switched the filter back on, i then went to work and when i returned i found the tank suffering, the filter had all but clogged and water quality was down, it was also cloudy. My tank background that had previously looked brown with diatoms was now almost back to its original colour.
Immediately i turned off the filter, removed the clogged sponge, tested for ammonia, nitrite, nitrate and PH, ammonia spike of 0.5 up from the 0 it usually tests at, nitrite was 0 and nitrates were maybe 10-20ppm, i tested ammonia again a little later and it was almost back at 0. I had 3 dead rosy tetras and 1 dead cardinal tetra. I removed dead fish straight away. I did a 40% water change over the next few hours (its a large tank) .
what happened?
I suspect the diatoms and algae died off and caused a spike in ammonia while i was at work and by the time i had got back from work was on its way back down, the filter being clogged shows just how much biological detritus was sent into the water column.

Has anyone else had similar experiences with HP, does my explanation sound right?

I was a little surprised at how effective at killing/removing algae and diatoms HP is and should of been a lot more careful, in hindsight i should of given myself the full day to monitor the tank and could of avoided fish deaths if i was here to catch the problems. I would warn those using HP to be prepared to deal with the ammonia spike from the dying bacteria and algae even though the HP is 'fish safe' when properly used.
Thanks
ADHDan

 

[jaylach]

I've heard of using hydrogen peroxide as a med but.... I just can't say that I agree and think it possible that it could be part of the issue.

What actual issue were the diatoms causing? I'm old school and sort of go by the rule of if it isn't broke, don't fix it. It reads like your water prams were good before treatment and you tried to fix what was not broken. Don't feel bad as we have all done something like this.

Others with more knowledge may give better advice but my advice would be to to do 30-40% water changes daily for a week to get rid of the hydrogen peroxide.

 

[Aqua67]

According to an article I found online at a Hydrogen Peroxide producer, this is what they recommend when treating the aquarium:

~~~~~~~~~~~
The agreeable amount of hydrogen peroxide is 1 ml per gallon of water of 3% hydrogen peroxide solution. In addition to that, you must do a significant water change after adding the chemical.

Various algal infestations require hydrogen peroxide concentration accordingly. The amount you use should not exceed 1.5 ml per gallon of water.
~~~~~~~~~~~

My first thought was also the same thing that you thought, the dying off of the algae created the ammonia spike too, and that may have also played a role. Too much hydrogen peroxide can burn fish gills and that may have also played a role.

 

[jaylach]

According to an article I found online at a Hydrogen Peroxide producer, this is what they recommend when treating the aquarium:

~~~~~~~~~~~
The agreeable amount of hydrogen peroxide is 1 ml per gallon of water of 3% hydrogen peroxide solution. In addition to that, you must do a significant water change after adding the chemical.

Various algal infestations require hydrogen peroxide concentration accordingly. The amount you use should not exceed 1.5 ml per gallon of water.
~~~~~~~~~~~

My first thought was also the same thing that you thought, the dying off of the algae created the ammonia spike too, and that may have also played a role. Too much hydrogen peroxide can burn fish gills and that may have also played a role.

Did you consider the possibility that they were just trying to sell hydrogen Peroxide?

 

[Aqua67]

Did you consider the possibility that they were just trying to sell hydrogen Peroxide?

The manufacturer’s site had all sorts of interesting articles about hydrogen peroxide, like mixing it with essential oils, using it to treat fungus on terrestrial plants, using it in aquariums, cleaning your ears, purifying water, taking playdough out of clothes, ……. I doubt there is any problem selling the stuff. It has many uses, for sure.

 

[GaryE]

H2O2 is a poison. A biocide. It works on algae, hydra and other creatures because of that.

I use it when tanks are in need of a crash response, but no fish are left in the tank for the dosing. I have had problems with tank and hydra, and it slaughters that beast. I have had fish eggs survive, to my surprise. But to poison a tank with fish in it? Nope. When I am shooting hydra with peroxide, via a syringe, I am extremely careful to keep amounts really low.

As an experiment, I treated a tank with H2O2 last week, to see if it would eliminate velvet. The velvet had eliminated the fish, a pair of killies, and it was the second time that tank, and only that tank, had had that parasite. I cleaned out the gravel, walloped the tank with a dose like you used and waited til I did a 95% water change. It's still cloudy and I'll do a total flush again this evening. I expected catastrophic results, and I got them.

 

[jaylach]

The manufacturer’s site had all sorts of interesting articles about hydrogen peroxide, like mixing it with essential oils, using it to treat fungus on terrestrial plants, using it in aquariums, cleaning your ears, purifying water, taking playdough out of clothes, ……. I doubt there is any problem selling the stuff. It has many uses, for sure.

And let's see... Chewey.com wants to sell me essential oils for my cockatiel yet they are toxic to the beastie. Please consider that the manufacturer's site is trying to sell a product to make money. They don't care about you, they just want your money.

 

[Aqua67]

And let's see... Chewey.com wants to sell me essential oils for my cockatiel yet they are toxic to the beastie. Please consider that the manufacturer's site is trying to sell a product to make money. They don't care about you, they just want your money.

What??!! I just went to Chewy’s website and searched for essential oils, and saw nothing for birds.

I have been a parrot keeper since the 1990s and I have over a dozen parrots of my own. I’ve been in BirdTalk magazine several times, written many parrot related articles, was the online editor for a national parrot society, was involved in parrot rescue, a two time award winning pet care volunteer, and even received a letter of recognition from my state senator for my expertise and dedication to educating people about their parrots. I handled a chat forum that received 3,000 posts a month asking for help with their parrots. I am a small business owner in a pet care field and I cannot imagine anyone suggesting essential oils for parrots. While it is true that birds in the wild will come into contact with the botanicals and barks that we use to create essential oils, they do not come into direct contact with the intensity of the concentrated oils. Cats are another pet that has problems with some essential oils (such as cinnamon, citrus, clove, etc.), while lavender has generally been used to help calm animals in stressful situations such as shelters/rescues. I would not recommend essential oils with parrots/birds though.

 

[Byron]

Hydrogen peroxide should absolutely never be added to an aquarium with fish. Never. Hydrogen peroxide is a powerful oxidizer; high doses can cause gill damage leading to fish mortality especially at high temperatures (Schmidt et al. 2006; Noga, 2010; Picon-Camcho et al. 2011). Yes, it says "high" doses, but it should be obvious to any aquarist that such a risky substance has no place in a fish tank, unless it is necessary to save the fish and is then the safest and most effective additive. This certainly is not the case with algae problems.

Problem algae is due to the imbalance of light and nutrients, and the only way to deal with it is to establish or re-establish that balance.

 

[adhdan]

Its all about the dose, its silly to say it should never be used when it can be used safely. A dose high enough to kill single celled organisms and low enough not to damage a fishes gills. There is always 'stuff' in a fishtank's water that is harmful to the fish, they have the ability to repair themselves the same as we do, if we breathed in dust for weeks or months it might prove fatal but walking into a dusty room for an hour ., My tap water has arsenic among other chemicals in it, but i still drink it and the fish live in it, (get your local water report and see what goodies you have in yours )
Plenty of people have used far higher doses then me or directly sprayed a fish whilst spot spraying algae and the general consensus is that it takes a far higher dose OR prolonged exposure to harm the fish, if your tank is full of bio matter (mine is a dirt substrate tank) then the HP oxidises incredibly quickly, i have no way of testing but ive read articles saying almost all is oxidised in the first 10minutes as long as there is plenty of flow and algae and bacteria in the tank. The HP turns into water and oxygen so nothing is left in your tank that needs flushing out after except for the broken down cells of what was oxidised.
Im sure there is someone far clever'er then me on here, feel free to correct me on anything ive said that is wrong

The diatoms werent causing any major issues, other then making the background brown and covering leaves of plants, i found the HP in my cupboard left over from a marine tank i had and i guess spur of the moment thought 'why not' , i just didnt expect it to have such as dramatic effect on the algae and diatoms as it did, previously in my marine tank battling cyanobacteria it took multiple doses over 10days to get visible effects

It wouldnt be the first time i thought i knew something and turned out to be mistaken, id just like to know what happened so i can avoid it when/if i use HP again, certainly i would dose less and do it on a day when i can be around to keep an eye on the system

 

[Byron]

If we understand the physioilogy of a fish we know that any substance added to the tank water will carry that substance into the fish's bloodstream. For anyone to even suggest this does not have consequences is comparable to the suggestion made a year ago that if we inject disinfectant (bleach) into our veins, we would kill covid.

 

[adhdan]

If we understand the physioilogy of a fish we know that any substance added to the tank water will carry that substance into the fish's bloodstream. For anyone to even suggest this does not have consequences is comparable to the suggestion made a year ago that if we inject disinfectant (bleach) into our veins, we would kill covid.

not a particularly helpful reply, by your logic I would be dead because my tap water contains arsenic and I ingest it and it gets into my blood stream but believe it or not I’m still here …alive …I hope

I agree it can’t be beneficial to the fish, but it doesn’t mean it does any lasting damage , if a fish needs to be exposed to X dose for X amount of time to get noticeable gill damage and we’re below that figure with HP dosing then we’re not harming the fish in any meaningful way .
If we truly wanted to do everything for the best health of the fish we wouldn’t keep them in glass boxes in our homes at all

 

[GaryE]

You're dug in on your tecnhique. You accidentally killed the fish with hydrogen peroxide.

Is there a way for a person with average resources to choose a safe dosage? Maybe, but why bother? It strikes me as a frivolous use of a product with easy overdosing issues. A similar example might be clove oil as a sedative. Yeah, it works, til an overdose gives you dead fish. This isn't trace elements of arsenic, and you know that.

You tried a risky technique based on one seller's site. You have dead fish. We are not set up to establish cause and effect for certain, but forget the 'ammonia spike' stuff. You played with biocides in a very closed system, and things you didn;t plan to kill get killed. Unfortunate, and I wouldn't do it again.

 

[adhdan]

You're dug in on your tecnhique. You accidentally killed the fish with hydrogen peroxide.

Is there a way for a person with average resources to choose a safe dosage? Maybe, but why bother? It strikes me as a frivolous use of a product with easy overdosing issues. A similar example might be clove oil as a sedative. Yeah, it works, til an overdose gives you dead fish. This isn't trace elements of arsenic, and you know that.

You tried a risky technique based on one seller's site. You have dead fish. We are not set up to establish cause and effect for certain, but forget the 'ammonia spike' stuff. You played with biocides in a very closed system, and things you didn;t plan to kill get killed. Unfortunate, and I wouldn't do it again.

to treat marine velvet a dose of

• 20 ml of 3% H2O2 per 1 gallon of saltwater for 30minute bath

Thats HP at 8x the dose rate i used in a sterile bowl and a single fish and that treatment was written by Humblefish

 

[jaylach]

What??!! I just went to Chewy’s website and searched for essential oils, and saw nothing for birds.

I have been a parrot keeper since the 1990s and I have over a dozen parrots of my own. I’ve been in BirdTalk magazine several times, written many parrot related articles, was the online editor for a national parrot society, was involved in parrot rescue, a two time award winning pet care volunteer, and even received a letter of recognition from my state senator for my expertise and dedication to educating people about their parrots. I handled a chat forum that received 3,000 posts a month asking for help with their parrots. I am a small business owner in a pet care field and I cannot imagine anyone suggesting essential oils for parrots. While it is true that birds in the wild will come into contact with the botanicals and barks that we use to create essential oils, they do not come into direct contact with the intensity of the concentrated oils. Cats are another pet that has problems with some essential oils (such as cinnamon, citrus, clove, etc.), while lavender has generally been used to help calm animals in stressful situations such as shelters/rescues. I would not recommend essential oils with parrots/birds though.

I MAY have spoken out of line about CHewy as it well could have been Petco. It was years ago... I haven't actually used Chewy for ages as they are just too expensive when you add in shipping.