Jessican
Sheriff
- Location
- San Antonio, TX
Update after eDNA testing: Peroxide (H2O2) dosing for parasites in reef tank
-----------------------------------------------------------------------------------------------------------------------------
*** The information contained here is only EXPERIMENTAL at the moment. Use at your own risk!!! ***
Disclaimer: I am in no way advocating this as a replacement for prophylactic quarantine or treatment in a hospital tank for active outbreaks. I think the decision to try to manage an outbreak in the display vs going fallow and treating with medication is going to be a personal one. I personally don’t think treatment in a hospital tank is always practical, especially when you have a large tank with large and/or numerous fish.
Important! Continue to run carbon while dosing peroxide. It may break the peroxide down faster, but it is necessary to prevent the buildup of toxic byproducts of oxidation. August 2020 update: Combining UV with peroxide is an advanced oxidation process used in drinking water treatment - the UV makes the peroxide more effective by raising its oxidation potential (in one link that I unfortunately can no longer find on the EPA's website, they stated that UV + peroxide is actually a better oxidizer than ozone or bleach). A number of us here have seen better success after adding UV to the equation. If you have it, use it.
Recommended use: Temporarily treating a parasite outbreak in a display tank while a hospital tank is acquired/set up, and fish are captured and moved. This can take the initial panic out of the equation and buy precious time for the fish. We don’t know for sure if this could eventually eliminate a parasite on its own without causing harm to the rest of the inhabitants, so long-term use is risky. August 2020 update: I have not seen any negative effects on the tanks or its inhabitants from dosing 1mL/5gal of 3% H2O2 for an extended period of time (>6 months).
-----------------------------------------------------------------------------------------------------------------------------
Treating an active outbreak with H2O2 dosing
At the beginning of this year, I was faced with a disease outbreak in my Reefer 525 (~139g system). I believe it was velvet. I’ve dealt with this before in my smaller tanks, and despite treatment with copper or cholorquine phosphate, still lost 8 out of 14 fish (57%). This time around, though, I’m dealing with a much larger tank, with much larger fish (still 14 total), and rockwork that couldn’t be removed to facilitate catching the fish. So I decided to try something somewhat unconventional: treating the velvet outbreak in the display by dosing peroxide.
I fortunately caught the outbreak early – only one fish had spots when I started dosing, and wasn’t showing any of the other outward signs of the disease (flashing, hiding from light, loss of appetite, or swimming in the flow of a powerhead).
I did wind up increasing the dosing frequency after this to every 3 hours, then every 1.5 hours during the day to try to keep the peroxide concentration up. Unfortunately, this is when I started to see algae issues, and wound up with spreading hair algae, as well as diatom and dino outbreaks, despite my nutrients staying relatively high, so I won’t get into that dosing schedule. I backed it off, and ultimately settled on this dosage:
I recommend dosing for a minimum of 6 weeks when treating an active outbreak, because we think that this method targets the free swimmers, so you need to dose for at least as long as tomonts might be present and actively releasing them. After 6 weeks, you can stop dosing and watch for signs that you need to start back up again.
For reference, using 3% peroxide:
1mL/10gal (40L) = 0.75ppm
1mL/8gal (30L) = 0.9ppm
1mL/5gal (19L) = 1.59ppm
1mL/3gal (11L) = 2.73ppm
1mL/1gal (4L) = 7.5ppm
-----------------------------------------------------------------------------------------------------------------------------
Other thoughts/concerns:
- Is it 100% reef safe? I'd say no, but what is? There's always a trade-off somewhere. Although I only lost 3 out of 14 fish (21%) with this method, I did lose several inverts and a few corals, although most did survive unscathed (whether the losses were directly due to the peroxide or due to the toxic byproducts that built up when I wasn’t running carbon, I can’t say). August 2020 update: Since re-adding carbon, I haven't had any more mysterious invert or coral losses, despite continuing to dose peroxide. In fact, things are thriving - see the FTS at the bottom of the page. I'm chalking these losses up to not using carbon early in the dosing. September 2020 update: I've since determined that the coral losses occurred not because of the lack of carbon, but because I dosed fenbendazole that was mislabeled as praziquantel. This might also explain some of the invert losses (especially snails) as well.
- Did I have far better fish outcomes than I would have if I'd pulled everyone into treatment and gone fallow? I believe so. I've seen far greater losses when I've treated with CP or copper in a hospital tank. The fish continued to behave normally, and I didn't see any appetite suppression the entire time, besides that one anthias that I lost.
However, caveat to that…:
- Do I think the parasite is gone? No, but I do think it's well controlled. After two months, I installed a UV sterilizer and discontinued the peroxide dosing. I will continue to watch closely in the coming months to see if I need to start back up again. August 2020 update: I have successfully added a number of new fish as outlined below and have discontinued dosing (although I am still running UV), with no sign of the disease returning so far.
- Would I take this approach again? Absolutely. No quarantine or treatment regimen is going to be 100% effective 100% of the time, so if something pops up again despite my best efforts, I will choose this method over going fallow.
FTS at the beginning of treatment (January 2020):
FTS at the end of treatment (March 2020):
-----------------------------------------------------------------------------------------------------------------------------
Maintenance dosing / adding new fish using H2O2 baths and dosing
After a couple of months of H2O2 dosing and then no dosing for a month, I was comfortable starting to add new fish to my display. However, I can't say for sure that the parasites are gone vs. just controlled, so I wanted to make sure that I was protecting the new fish from anything still lurking in the tank.
My thought here is that if I start with reasonably clean fish, give them a 150ppm peroxide bath to knock off anything they might be carrying, and then add them to the DT where I dose peroxide for a minimum of a month, the fish will be protected from anything that might be lurking while they build up their own immunity.
Here's the method:
- New fish that I would consider reasonably clean to start with (such as Diver’s Den or Biota/ORA) gets a 150ppm bath for 30 min
- New fish goes into the display, with UV running 24/7
- For at least a month after, I dose peroxide at 1mL/5gal, 3x a day
- After the month is up, I’ll stop the peroxide but keep running the UV (I plan to eventually try turning off the UV as well and black molly testing, but I don’t know when yet)
Using this method, I’ve successfully added the following fish to my tanks:
- Rainford goby
- Swales Swissguard basslet
- Bluestreak cleaner wrasse
- Blue throat triggerfish
- Hooded fairy wrasse (this one didn’t get the initial bath because she was already QT’d)
- Bicolor foxface
- Orchid dottyback
- Banggai cardinal
- Melanurus wrasse
- Ocellaris clownfish
I’ve also successfully moved a yellow candy hogfish and a possum wrasse from a previously infected tank to a clean tank with only UV running (no dosing) with only a peroxide bath in between. I also haven't lost any of my existing fish while adding new fish. I spent probably two months total doing additional dosing while adding fish.
One thing I do want to point out - none of these fish are ich magnets, like tangs. To add those, I would suggest starting peroxide dosing for a couple weeks prior to adding them, to knock down the number of potential free swimmers, and then dose for a minimum of a month after adding. You probably don’t need to do the continuous overnight dosing if you don’t have an active outbreak, but just pay very close attention to behavior - you can always up the dosing if you see signs.
-----------------------------------------------------------------------------------------------------------------------------
Final thoughts
Despite the caveats and warnings above, I'm pretty confident in the effectiveness of the peroxide dosing for at least disease management, if not eradication. My tank is thriving, the fish are healthy, I've been able to add new fish, and I haven't lost anyone to disease since I started. The only thing left to do is to black molly test the DT once the current UV bulb dies (it's been running for 6 months now) and see if I hit for anything. At this point, I highly recommend this method to anyone who is either unable to use a QT tank, or getting burnt out on the cycle of disease outbreaks and treatments - sometimes even when you do everything right, things still go wrong.
Final FTS, eight months after this all started (August 2020):
-----------------------------------------------------------------------------------------------------------------------------
*** The information contained here is only EXPERIMENTAL at the moment. Use at your own risk!!! ***
Disclaimer: I am in no way advocating this as a replacement for prophylactic quarantine or treatment in a hospital tank for active outbreaks. I think the decision to try to manage an outbreak in the display vs going fallow and treating with medication is going to be a personal one. I personally don’t think treatment in a hospital tank is always practical, especially when you have a large tank with large and/or numerous fish.
Important! Continue to run carbon while dosing peroxide. It may break the peroxide down faster, but it is necessary to prevent the buildup of toxic byproducts of oxidation. August 2020 update: Combining UV with peroxide is an advanced oxidation process used in drinking water treatment - the UV makes the peroxide more effective by raising its oxidation potential (in one link that I unfortunately can no longer find on the EPA's website, they stated that UV + peroxide is actually a better oxidizer than ozone or bleach). A number of us here have seen better success after adding UV to the equation. If you have it, use it.
Recommended use: Temporarily treating a parasite outbreak in a display tank while a hospital tank is acquired/set up, and fish are captured and moved. This can take the initial panic out of the equation and buy precious time for the fish. We don’t know for sure if this could eventually eliminate a parasite on its own without causing harm to the rest of the inhabitants, so long-term use is risky. August 2020 update: I have not seen any negative effects on the tanks or its inhabitants from dosing 1mL/5gal of 3% H2O2 for an extended period of time (>6 months).
-----------------------------------------------------------------------------------------------------------------------------
Treating an active outbreak with H2O2 dosing
At the beginning of this year, I was faced with a disease outbreak in my Reefer 525 (~139g system). I believe it was velvet. I’ve dealt with this before in my smaller tanks, and despite treatment with copper or cholorquine phosphate, still lost 8 out of 14 fish (57%). This time around, though, I’m dealing with a much larger tank, with much larger fish (still 14 total), and rockwork that couldn’t be removed to facilitate catching the fish. So I decided to try something somewhat unconventional: treating the velvet outbreak in the display by dosing peroxide.
I fortunately caught the outbreak early – only one fish had spots when I started dosing, and wasn’t showing any of the other outward signs of the disease (flashing, hiding from light, loss of appetite, or swimming in the flow of a powerhead).
- Starting dose: 1mL per 8 gallons (15mL) every 12 hours
- Week 2: increased to 1mL per 8 gallons (15mL) every 8 hours
- Week 4: increased to 1mL per 5 gallons (24mL) every 8 hours, and added overnight dosing (1mL every 15 minutes for 6 hours)
I did wind up increasing the dosing frequency after this to every 3 hours, then every 1.5 hours during the day to try to keep the peroxide concentration up. Unfortunately, this is when I started to see algae issues, and wound up with spreading hair algae, as well as diatom and dino outbreaks, despite my nutrients staying relatively high, so I won’t get into that dosing schedule. I backed it off, and ultimately settled on this dosage:
- 1mL per 5 gallons (24mL) every 8 hours, just before lights on, midday, and just after lights off.
- 2mL every 15 minutes for 6 hours overnight (for a total of 48mL, or 2x a normal daytime dose)
I recommend dosing for a minimum of 6 weeks when treating an active outbreak, because we think that this method targets the free swimmers, so you need to dose for at least as long as tomonts might be present and actively releasing them. After 6 weeks, you can stop dosing and watch for signs that you need to start back up again.
For reference, using 3% peroxide:
1mL/10gal (40L) = 0.75ppm
1mL/8gal (30L) = 0.9ppm
1mL/5gal (19L) = 1.59ppm
1mL/3gal (11L) = 2.73ppm
1mL/1gal (4L) = 7.5ppm
-----------------------------------------------------------------------------------------------------------------------------
Other thoughts/concerns:
- Is it 100% reef safe? I'd say no, but what is? There's always a trade-off somewhere. Although I only lost 3 out of 14 fish (21%) with this method, I did lose several inverts and a few corals, although most did survive unscathed (whether the losses were directly due to the peroxide or due to the toxic byproducts that built up when I wasn’t running carbon, I can’t say). August 2020 update: Since re-adding carbon, I haven't had any more mysterious invert or coral losses, despite continuing to dose peroxide. In fact, things are thriving - see the FTS at the bottom of the page. I'm chalking these losses up to not using carbon early in the dosing. September 2020 update: I've since determined that the coral losses occurred not because of the lack of carbon, but because I dosed fenbendazole that was mislabeled as praziquantel. This might also explain some of the invert losses (especially snails) as well.
Invert losses: All trochus, margarita, and turbo snails, 1 tropical abalone, 2 cleaner shrimp, 1 pincushion urchin, and 1 maxima clam (not dead yet, but not looking great, so I expect I'll likely lose it)
Coral losses: Only softies/polyps (pipe organ coral, toadstool leather, finger leather, purple gorgonian, several kenya trees)
Invert survivors: All nerite, cerith, and bumblebee snails, all money cowries, 1 tropical abalone, fighting conch, electric flame scallop, various hermit/pitho/strawberry/pom pom crabs, rock flower/BTA/mini carpet anemones, 1 cleaner shrimp, 1 sexy shrimp 3 urchins (tuxedo, short spine, and Halloween), and 1 maxima clam. The BTAs actually continued to split like crazy while I was doing this – there were probably 12 in the tank when I started, and that number at least doubled.
Coral survivors: SPS frags (pocillapora, millepora, digitata, bonsai acro, various montis, psammacora, potato chip, elephant skin), large monti cap, variety of LPS (frogspawns, hammers, torches, cristata, acans, favias, pearl bubble, leptastrea, gonis/alveoporas, moseleya, fungia plate, turbinara, duncans, lobos, galaxea, blastos, candy cane, pectinia), one zoa colony (it actually went from 2 polyps to 5), and several mushrooms
- Did I have far better fish outcomes than I would have if I'd pulled everyone into treatment and gone fallow? I believe so. I've seen far greater losses when I've treated with CP or copper in a hospital tank. The fish continued to behave normally, and I didn't see any appetite suppression the entire time, besides that one anthias that I lost.
However, caveat to that…:
- Do I think the parasite is gone? No, but I do think it's well controlled. After two months, I installed a UV sterilizer and discontinued the peroxide dosing. I will continue to watch closely in the coming months to see if I need to start back up again. August 2020 update: I have successfully added a number of new fish as outlined below and have discontinued dosing (although I am still running UV), with no sign of the disease returning so far.
- Would I take this approach again? Absolutely. No quarantine or treatment regimen is going to be 100% effective 100% of the time, so if something pops up again despite my best efforts, I will choose this method over going fallow.
FTS at the beginning of treatment (January 2020):
FTS at the end of treatment (March 2020):
-----------------------------------------------------------------------------------------------------------------------------
Maintenance dosing / adding new fish using H2O2 baths and dosing
After a couple of months of H2O2 dosing and then no dosing for a month, I was comfortable starting to add new fish to my display. However, I can't say for sure that the parasites are gone vs. just controlled, so I wanted to make sure that I was protecting the new fish from anything still lurking in the tank.
My thought here is that if I start with reasonably clean fish, give them a 150ppm peroxide bath to knock off anything they might be carrying, and then add them to the DT where I dose peroxide for a minimum of a month, the fish will be protected from anything that might be lurking while they build up their own immunity.
Here's the method:
- New fish that I would consider reasonably clean to start with (such as Diver’s Den or Biota/ORA) gets a 150ppm bath for 30 min
- New fish goes into the display, with UV running 24/7
- For at least a month after, I dose peroxide at 1mL/5gal, 3x a day
- After the month is up, I’ll stop the peroxide but keep running the UV (I plan to eventually try turning off the UV as well and black molly testing, but I don’t know when yet)
Using this method, I’ve successfully added the following fish to my tanks:
- Rainford goby
- Swales Swissguard basslet
- Bluestreak cleaner wrasse
- Blue throat triggerfish
- Hooded fairy wrasse (this one didn’t get the initial bath because she was already QT’d)
- Bicolor foxface
- Orchid dottyback
- Banggai cardinal
- Melanurus wrasse
- Ocellaris clownfish
I’ve also successfully moved a yellow candy hogfish and a possum wrasse from a previously infected tank to a clean tank with only UV running (no dosing) with only a peroxide bath in between. I also haven't lost any of my existing fish while adding new fish. I spent probably two months total doing additional dosing while adding fish.
One thing I do want to point out - none of these fish are ich magnets, like tangs. To add those, I would suggest starting peroxide dosing for a couple weeks prior to adding them, to knock down the number of potential free swimmers, and then dose for a minimum of a month after adding. You probably don’t need to do the continuous overnight dosing if you don’t have an active outbreak, but just pay very close attention to behavior - you can always up the dosing if you see signs.
-----------------------------------------------------------------------------------------------------------------------------
Final thoughts
Despite the caveats and warnings above, I'm pretty confident in the effectiveness of the peroxide dosing for at least disease management, if not eradication. My tank is thriving, the fish are healthy, I've been able to add new fish, and I haven't lost anyone to disease since I started. The only thing left to do is to black molly test the DT once the current UV bulb dies (it's been running for 6 months now) and see if I hit for anything. At this point, I highly recommend this method to anyone who is either unable to use a QT tank, or getting burnt out on the cycle of disease outbreaks and treatments - sometimes even when you do everything right, things still go wrong.
Final FTS, eight months after this all started (August 2020):
Last edited:
