Hydrogen Peroxide Treatment for Shrimp | Uses & Safe Dosage

Don't worry. We're not bleaching the shrimp, but curing them! Although salt is our preferred first line of treatment when our favorite pet crustaceans fall ill, sometimes we need something a little stronger. Hydrogen peroxide treatment for shrimp is perfectly safe when done correctly, so let's take a look at how to use it and where exactly it can come in useful.

Is hydrogen peroxide treatment for shrimp safe?

Yes, hydrogen peroxide treatment for shrimp is well-tolerated. We have heard of die-offs happening, but these are usually related to cycle crashes post-treatment; you can prevent this by taking the filter out of the tank before you add the hydrogen peroxide. Still, there's always a small risk, especially if you accidentally overdose. That's we don't necessarily recommend hydrogen peroxide treatment for aesthetic purposes, like to treat pesky black beard algae (BBA).

Even for shrimp suffering from infestations, we think trying salt treatment first is the way to go. Salt dips work very well against a variety of unwelcome critters, plus they're very unlikely to damage your shrimp even if you overdo it a little. Save the H₂O₂ for cases where NaCl alone doesn't do it, or the pathogen responsible doesn't respond to it. Many bacteria can live in both fresh and saltwater, for example, so salt dips won't help against infections.

When should I use hydrogen peroxide?

Shrimpers use hydrogen peroxide to get rid of a wide variety of living things they don't want in their tanks or on their shrimp. As mentioned above, there is a small risk, so it's up to you in which cases you consider H₂O₂ worth it. Do remember that almost all shrimp-related problems can be traced back to poor water quality and excess nutrients. If you don't fix these issues first, the disease or infestation will most likely simply come back.

You can consider hydrogen peroxide when dealing with:

• Infestations that haven't gone away with salt dips, like Vorticella, Scutariella, and H. truncatus
• Infestations that don't respond (much) to salt, like oomycetes and Cladogonium
• External bacterial infection (chitinolytic shell disease)
• Persistent pest hitchhikers, like Hydra (though again, try to reduce feedings + increase cleaning first)
• Persistent algae, like BBA (though we prefer good old-fashioned scrubbing)

Why does hydrogen peroxide work?

You're probably familiar with hydrogen peroxide as a bleaching agent, cleaning chemical, and disinfectant for minor scrapes and cuts. The reason H₂O₂ is so effective at all these things is because it causes organic material to oxidize incredibly quickly.

Even if your chemistry is rusty, you may remember that oxidizing agents strip electrons from atoms they come into contact with. The resulting "panic" at the molecular level — affected atoms scrambling to steal back electrons from whichever neighbor they can find — destroys and disrupts fats, proteins, enzymes, and even DNA. Protective membranes are broken down, metabolisms disrupted, and conditions become generally incompatible with life.

The reason your shrimp (and you) can survive coming into contact with hydrogen peroxide while bacteria and parasites die is that they (and we) are simply bigger. We have less surface area, plus our cells are better at dealing with oxidative stress than those of smaller and less complex organisms.

All creatures will die if exposed to enough H₂O₂, so the trick is to find a concentration that kills the pathogen but not the innocent victim. This explains why messing up the dosage can cause shrimp losses: as with most medical treatments, the dose makes the poison. Luckily, other shrimpers have gone before you and figured out how much to use for the best results.

Hydrogen peroxide treatment for shrimp

You can use any brand of pure, unscented 3% hydrogen peroxide — found at drugstores or online — to treat sick shrimp. Unless your shrimp tank is very large, you only need a small bottle. Always check the expiration date, because expired H₂O₂ does lose (some of) its efficacy!

For the dosage, we'll have to rely entirely on hobbyist sources. There are exactly zero published scientific experiments that measure how much hydrogen peroxide dwarf shrimp can handle per dose. The closest thing we found is a paper on Macrobrachium (whisker) shrimp, but those were exposed to the H₂O₂ for a whopping 96 hours. Our pet shrimp will only be in contact with the until the dose dissipates, which takes less than an hour.

Your hydrogen peroxide treatment plan starts with a water change. There are three reasons for this: you need half a bucket of tank water, it makes dosing more accurate (excess organic material causes H₂O₂ to deplete more quickly), and it helps prevent broken-down organic waste from potentially causing an ammonia spike after treatment.

Here's how it works:

• Perform a regular 20% water change and vacuum the substrate a few hours before you want to treat with hydrogen peroxide. DO NOT throw out the water you removed from the tank. You will need it!
• Calculate the gross water volume of the tank to be treated if you don't know it. Length × width × height in inches = volume in gallons.
• Calculate the true water volume by accounting for substrate and decorations (if you think 25% of your tank is taken up by sand and rocks, multiply the volume by 0.75, for example). This is important to avoid overdosing your shrimp on H₂O₂.
• Take the filter out of the aquarium and run it in the bucket of tank water you saved. H₂O₂ kills nitrifying bacteria, and just turning the filter off is too risky. Moving it helps prevent cycle bumps, which cause many more shrimp deaths than hydrogen peroxide does, while maintaining the flow level the bacteria love.
• You can leave on the tank lights. Sunlight and UV sterilizers degrade H₂O₂, but LED or fluorescents barely do because they don't emit UV-C. Most guides recommend turning off the lights, but the difference will be negligible.
• Measure out 1.5ml of hydrogen peroxide per 1 gallon of true water volume. Sorry, no messing around with teaspoons here: a syringe works best. Your water test kit may contain one.
• Add the peroxide to a cup of tank water and pour it in, mixing very gently but very thoroughly to ensure it reaches every corner and every shrimp. Try not to dump everything in one spot.
• Set a timer for one hour. If your shrimp seem to struggle (which is unlikely to happen*), dose 2-3x the standard amount of your normal water conditioner and mix well. Dechlorinators rapidly neutralize hydrogen peroxide.
• Move the filter back to the tank. The hydrogen peroxide has done its work and has been depleted, so no need for another water change. Do keep an eye on the ammonia reading, just in case!

*You can observe the babies in particular. They've been shown to be less resistant to hydrogen peroxide than the adults. If the little ones are fine during treatment, the rest of the colony most likely is as well.

If you're treating for an epibiont infestation like Scutariella, your shrimp could be free of adult worms after just one hydrogen peroxide treatment (though you may have to repeat as eggs hatch). More serious diseases like bacterial rust may require treatment every few days for a week or two, basically until the affected shrimp molt off the infection or die. You can consider moving them to a quarantine system to make treatment easier and protect the nitrifying bacteria in the display tank.