Molting versus Muerte

[jefferypink]

Molt vs Muerte: The mystery of the missing shrimp deepens

So back to the hobby after 10 years or so. I have a 29 gallon, The first occupant is a koi betta, then I added 5-6 amano shrimp; They looked bigger in the store than when I brought them home. Betta was intensely curious about these fast-moving bugs I put in his home. After a couple days, the shrimp disappeared. I presumed they were in hiding since reading a similar post on a google search that they can hide for several days. Soon I added more tank mates to distract Emperor Staleek the betta, 10 black neon Tetras, whom he has decided are not worthy of his attention. Then 6 Otocinclus to entertain the emperor with their antics. 

I cut the amount of hours the light was on, and have made sure there is a piece of zucchini or algae wafer in the tank at night, presuming the shrimp are coming out then. Twice, late at night while examining the tank with a dim led candle, I have seen exactly one shrimp still alive, near the big rock that I'm afraid to move to check under cuz it would really squish 'em if it slipped. As I posted in my introduction, It's now been 6 days since I've seen a shrimp alive. Today I found what I'm 99% sure is a shrimp molt, but since I've never kept shrimp before, I could be wrong. (I used to catch crayfish from a creek and have seen them molt before, though)

*Is there any way to tell the difference between a molt and a carcass?*

I'd presume a carcass would have been covered in snails or maybe the otos. I took out the molt with tweezers, it doesn't smell fishy, there's no obvious pieces of flesh, it's clear, there's a gap between the head and abdomen where I presume the moltee left its former shell.

My new theory is that when I added them to the tank they were so small and I fed them so much they grew and hid to molt, and I hope to see more of them when they harden back up. Any other thoughts or suggestions?

P.S. Lid is glass, aqueon tank has a black plastic rim, but there are gaps small enough for shrimp to have escaped; no bodies have been found outside the tank and none in the Fluval C2 Hob. Lots of cholla wood that is hollow in the tank as well. 

[Martin]

That looks like a molt to me.  Alternatively, I have found with my ghost shrimp that they are very active foragers and have had instances in the past where either another shrimp or small fish died and the shrimp consumed the body quickly to where there was very little to judge by the time I got curious and started looking.  My current tank has 5 shrimp however I have recently only seen 4 at any one time.  It's pretty heavily planted so, like you, I can never tell if the 5th one is just hiding or if I lost one.

[Brandy]

looks like a molt! Saying they can "hide for a few days" is very misleading. They can be flat out invisible for MONTHS. Shrimp are masters of hiding. Seeing fresh molts is a very good sign.

[jefferypink]

Thanks, that's very re-assuring. 😃