Parasitic Isopod?

[Radiofox05]

I don’t know if this is the best forum to post this in, but I hope this is okay! My pederson shrimp has had an odd white lump on his side, that I for some reason assumed was normal, until I realized today that it has grown larger (see pic). I’m fairly certain it’s a parasitic isopod, but how can i go about removing it? I know people can do it but with bigger shrimp, it’ll be hard getting my little guy to sit still. Thanks in advance!

 

[Jay Hemdal Verified Community Expert]

I don’t know if this is the best forum to post this in, but I hope this is okay! My pederson shrimp has had an odd white lump on his side, that I for some reason assumed was normal, until I realized today that it has grown larger (see pic). I’m fairly certain it’s a parasitic isopod, but how can i go about removing it? I know people can do it but with bigger shrimp, it’ll be hard getting my little guy to sit still. Thanks in advance!

Welcome to Reef2Reef!

That does look like a parasitic isopod, but I've not seen that on small cleaner shrimp like that (but I haven't had many of those).

Here is some text that I wrote about that:

Some species of shrimp (notably the skunk cleaner shrimp, Lysmata sp.) arrive with epicaridean isopod infections that look like white lumps on the side of the shrimp’s abdomen. Since the isopod is a crustacean itself, there is no treatment that will affect the parasite without killing the shrimp. Surgical removal is also not advised because crustaceans can only repair damage to their shells when they molt, so when the isopod is removed, a large wound will remain.

 

[Radiofox05]

I don’t know if this is the best forum to post this in, but I hope this is okay! My pederson shrimp has had an odd white lump on his side, that I for some reason assumed was normal, until I realized today that it has grown larger (see pic). I’m fairly certain it’s a parasitic isopod, but how can i go about removing it? I know people can do it but with bigger shrimp, it’ll be hard getting my little guy to sit still. Thanks in advance!

Welcome to Reef2Reef!

That does look like a parasitic isopod, but I've not seen that on small cleaner shrimp like that (but I haven't had many of those).

Here is some text that I wrote about that:

Some species of shrimp (notably the skunk cleaner shrimp, Lysmata sp.) arrive with epicaridean isopod infections that look like white lumps on the side of the shrimp’s abdomen. Since the isopod is a crustacean itself, there is no treatment that will affect the parasite without killing the shrimp. Surgical removal is also not advised because crustaceans can only repair damage to their shells when they molt, so when the isopod is removed, a large wound will remain.

Thank you for the response! In lieu of surgery, what are my options? I’m assuming the isopods will release their eggs at some point; would that kill my shrimp, or harm my other crustaceans?

 

[Jay Hemdal Verified Community Expert]

Thank you for the response! In lieu of surgery, what are my options? I’m assuming the isopods will release their eggs at some point; would that kill my shrimp, or harm my other crustaceans?

I don't know - I presume that these parasitic isopods have a larval stage that is not able to be completed in an aquarium (needing multiple hosts, or having a delicate planktonic larva that cannot live in aquariums). The main issue seems to be if the shrimp can survive until its next molt.....

 

[Radiofox05]

Thank you for the response! In lieu of surgery, what are my options? I’m assuming the isopods will release their eggs at some point; would that kill my shrimp, or harm my other crustaceans?

I don't know - I presume that these parasitic isopods have a larval stage that is not able to be completed in an aquarium (needing multiple hosts, or having a delicate planktonic larva that cannot live in aquariums). The main issue seems to be if the shrimp can survive until its next molt.....

I believe they do have a free-swimming larval stage, yes! My shrimp has survived since early January with this thing, although I’m not sure I’ve ever seen him molt. Is there anything extra I could dose, like calcium or magnesium, to hurry along his molting process?

 

[Jay Hemdal Verified Community Expert]

I believe they do have a free-swimming larval stage, yes! My shrimp has survived since early January with this thing, although I’m not sure I’ve ever seen him molt. Is there anything extra I could dose, like calcium or magnesium, to hurry along his molting process?

It used to be said in the public aquarium world, that dosing iodine would help crustaceans to molt, but in practice, that never really helps.

I think age is the only factor - smaller / younger shrimp molt more frequently. Some shrimp also have a terminal molt, where they just don’t molt again.

 

[Radiofox05]

I believe they do have a free-swimming larval stage, yes! My shrimp has survived since early January with this thing, although I’m not sure I’ve ever seen him molt. Is there anything extra I could dose, like calcium or magnesium, to hurry along his molting process?

It used to be said in the public aquarium world, that dosing iodine would help crustaceans to molt, but in practice, that never really helps.

I think age is the only factor - smaller / younger shrimp molt more frequently. Some shrimp also have a terminal molt, where they just don’t molt again.

Ah, okay! Thank you very much for your advice, by the way, I appreciate it!