formallydehyde
Active Member
Too long; didn't read: I lost both a peppermint shrimp and a fire shrimp after using hydrogen peroxide spot treatment to get rid of a bad dinoflagellate outbreak in separate incidents. Both died during the night after treatment. Others have reported similar incidents. Don't use hydrogen peroxide treatment in a tank that has shrimp.
More detailed version:
I had two peppermint shrimp and one fire shrimp in a 20 gallon tank that ended up with a bad dinoflagellate outbreak. Part of the reason that I decided to treat the outbreak with peroxide was ironically that my fire shrimp *hated* stepping on the dinoflagellate mats. Every source I initially read said it was safe for invertebrates.
The first time I peroxide treated, I lost a peppermint shrimp but did not connect the peroxide to her death because the other peppermint shrimp survived, as well as my fire shrimp. So I thought it was a coincidence, and that the treatment was safe. I treated a second time without incident, though the two remaining shrimp looked a little irritated but nothing major.
The third time I peroxide treated, my fire shrimp started acting weird soon after, and she died that night. I performed some huge water changes after she started acting strange but it was already too late. Then I started looking deeper on here to see if there was a connection, and sure enough, other people had reported deaths of Lysmata genus shrimp after peroxide treatment. Unfortunately, this info was buried replies to larger threads about algae treatment, so I did not see them in time. If I had, I would have never used this method at all. From what I remember that others have said, it seems like death can happen even from small spot treatments in larger tanks or low doses in the water itself. So I don't think there's any shrimp-safe way to do it.
All my shrimp were named and I loved them a lot, my fire shrimp Socks in particular, was the star of my tank and I looked forward to seeing her excitedly pop out to beg for food when I got home from work. Her dying from my stupid decisions was really hard and it consequently took me a while after this happened to write this post.
My suspicion is shrimp are more susceptible to death from peroxide than other crustaceans because of how much more frequently they molt, and maybe their relative sensitivity to it depends on where they're at in their molt cycle. Some parts of Socks' remains looked like partially formed exoskeleton and both shrimp deaths happened late during the night, which is the time they always molted. Both were alive and active before then, so my educated guess is for some reason peroxide can trigger a premature, partial molt, which results in death. Shrimp also deal with exoskeletal infections by molting much more frequently, though these are usually complete molts, for what that's worth. The only surviving shrimp from this ordeal was the runtier peppermint shrimp, Junior, who molted far more infrequently than the other two shrimp. Junior is still alive today, actually. But again, this is all speculation.
I am also not 100% certain whether or not the lethality was from the peroxide *itself*, or possibly some kind of toxin released from a large number of dinoflagellates dying all at once. Regardless of if it's the immediate cause of death or just triggers another deadly event, I think this needs to be more well known that this method is not as harmless as it's often stated to be.
I know this is maybe more of an invert care post, but it's not like anyone is treating their tanks with hydrogen peroxide for anything besides algae outbreaks. Anyway, hopefully this will save a few shrimp.
More detailed version:
I had two peppermint shrimp and one fire shrimp in a 20 gallon tank that ended up with a bad dinoflagellate outbreak. Part of the reason that I decided to treat the outbreak with peroxide was ironically that my fire shrimp *hated* stepping on the dinoflagellate mats. Every source I initially read said it was safe for invertebrates.
The first time I peroxide treated, I lost a peppermint shrimp but did not connect the peroxide to her death because the other peppermint shrimp survived, as well as my fire shrimp. So I thought it was a coincidence, and that the treatment was safe. I treated a second time without incident, though the two remaining shrimp looked a little irritated but nothing major.
The third time I peroxide treated, my fire shrimp started acting weird soon after, and she died that night. I performed some huge water changes after she started acting strange but it was already too late. Then I started looking deeper on here to see if there was a connection, and sure enough, other people had reported deaths of Lysmata genus shrimp after peroxide treatment. Unfortunately, this info was buried replies to larger threads about algae treatment, so I did not see them in time. If I had, I would have never used this method at all. From what I remember that others have said, it seems like death can happen even from small spot treatments in larger tanks or low doses in the water itself. So I don't think there's any shrimp-safe way to do it.
All my shrimp were named and I loved them a lot, my fire shrimp Socks in particular, was the star of my tank and I looked forward to seeing her excitedly pop out to beg for food when I got home from work. Her dying from my stupid decisions was really hard and it consequently took me a while after this happened to write this post.
My suspicion is shrimp are more susceptible to death from peroxide than other crustaceans because of how much more frequently they molt, and maybe their relative sensitivity to it depends on where they're at in their molt cycle. Some parts of Socks' remains looked like partially formed exoskeleton and both shrimp deaths happened late during the night, which is the time they always molted. Both were alive and active before then, so my educated guess is for some reason peroxide can trigger a premature, partial molt, which results in death. Shrimp also deal with exoskeletal infections by molting much more frequently, though these are usually complete molts, for what that's worth. The only surviving shrimp from this ordeal was the runtier peppermint shrimp, Junior, who molted far more infrequently than the other two shrimp. Junior is still alive today, actually. But again, this is all speculation.
I am also not 100% certain whether or not the lethality was from the peroxide *itself*, or possibly some kind of toxin released from a large number of dinoflagellates dying all at once. Regardless of if it's the immediate cause of death or just triggers another deadly event, I think this needs to be more well known that this method is not as harmless as it's often stated to be.
I know this is maybe more of an invert care post, but it's not like anyone is treating their tanks with hydrogen peroxide for anything besides algae outbreaks. Anyway, hopefully this will save a few shrimp.
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