Help ID grass shrimp ulcer/disease

[Pugio]

I have some P. paludosus grass shrimp and one was carrying an odd-looking red ulcer on its shell for at least 3+ days since I noticed it. This shrimp seemed to behave normally and I was waiting for it to molt to see if spot went away - 'lo and behold I came home today and saw same shrimp very much dead. When it was alive the red ulcer had a thin black border. No fish in tank; no recent trauma; no other shrimp noted to have this. Here's 2 views:



Would appreciate any help with this, esp. if it's infectious. Thanks folks!

[marusempai]

One of the ghost shrimp in my latest batch had this EXACT same thing. I don't know what it is either, but it doesn't seem to be contageous -- the ulcerated shrimp was in quarantine with one with one of those intestinal worms, the ulcer shrimp died on about the fourth or fifth day, but it's buddy never got the ulcer. Eventually passed the worm and the shrimp is still living happily in my tank.

[Mustafa]

Not sure exactly what it is, but it's most likely a bacterial infection.

[Pugio]

Thanks - I haven't seen it on other shrimp yet. I assume the shrimp arrived with it and I missed it at an earlier stage. Interesting to hear it was on someone else's ghost shrimp. Reminds me to keep better quarantine measures - jeez.

[Pugio]

Found another P. paludosus with an "ulcer" today. Kinda worried as you can see one of my orange shrimps in the background.

Not sure how helpful the low power micrograph is. Ulcer again appears at the junction of two abdominal segments. Not sure how to control this if a bacterial infection.

[marusempai]

Maybe you could try Melafix? Supposedly it is shrimp safe, I know it is snail safe but have never tried it on shrimp. Isolating any sick one/s is probably a good idea too.