Shrimps keep disappearing/dying

I used to have very good luck with shrimps. Used to have one skunk cleaner, one fire shrimp, 2 peppermint shrimp and 2 pistol shrimps. Started just before Christmas with the disappearance of my fire shrimp. First thought he was molting but when he did not come out after a week I started to think he had died. the peppermint shrimps all of a sudden disappeared as well with no explanation. Last week the same happened to my trusty skunk cleaner.

Last weekend I added a new Fire shrimp and he seemed OK after the acclimatizing. The next morning he was gone as well. He could still be molting but I have not seen a trace of him so I fear the worst. What could explain this?

My water parameters as of yesterday is:

Temp: 78.5

S.G 1.026

Alk.: 6.2

Ca: 565

Mg: 1550

Ammonia: 0

Nitrite: 0

Nitrate: 20

Phos: 0.25

Sounds like your pistol shrimp are having quite a few shrimp dinners. That would be my best guess, especially if your pistols are larger then the rest of your disappearing shrimp?

The pistol is a Tiger Pistol and is about 1" long. That is still much smaller than both the Fire shrimp and the skunk cleaner. The "original cast" lived happily together for months before this started to happen.

Could there be some other predator lurking in the tank? Maybe a mantis?

Quote:

Originally Posted by Mike_Noren



Could there be some other predator lurking in the tank? Maybe a mantis?

Or an opportunistic crab of some kind? Some hitchhikers come in with the live rock really small and only after they grow and start eating larger prey do they start getting noticed. Maybe leave a trap of some kind with a piece of shrimp and see what you can catch.

Have not seen any crabs or mantis shrimps in the tank since day 1. I did add a emerald crab this weekend but that was after all the shrimp deaths.

Did found a "dead body" when I came home today. It was covered in some sort of "net" or "dust ball".

What else can take out a shrimp - Probably nocturnal, must be fairly large, very stealthy, and an easily missed hitchhiker?

I have tried to stay up a couple of hours after lights out but have not seen anything that could pose a threat. My tank is very small, 28g cube, so there are not many hiding places for something big. I do have serpent sea star but i have never heard about them taking out any fish or shrimps before.

This is a real mystery. I will see if I can get one or two Peppermint shrimps later this week and monitor them real close to see what I can find.

i would be more concerned with salinity swings they will kill a shrimp in a blink off an eye

I have been hoovering between 1.025-1.026 more or less since day one. But I don't check it every day, just once a week. This is of course assuming that my refractometer is working as it should. Maybe I should take my water to my LFS to have them do a water test as well to rule out that possibility?

Quote:

Originally Posted by ojonas81



...I do have serpent sea star but i have never heard about them taking out any fish or shrimps before.

This is a real mystery. I will see if I can get one or two Peppermint shrimps later this week and monitor them real close to see what I can find.

Years ago, I had a green serpent star that got large and appeared to eat a shrimp. This could be your problem. Mine was sent to the fuge and no additional losses occurred. Not proof, but some evidence anyway.

I was gonna say the same thing...what color is that star?