Mystery crabs appearing in Aquarium

[BillyBuckshot]

I have a tank with 3 small blue crabs. In the last 2 weeks I’ve had 4 mystery blue crabs show up. I can’t explain it. All were freshly dead, but the one today had climbed up to a platform in the tank and died. I think I’m losing my mind. There’s no reasonable explanation for it. There’s really no where they could of hidden. No one came by my house and snuck an extra crab in my tank to mess with me.
The shells in the tank were far too small to stowaway in.
I noticed there’s a couple people on here that have posted something similar but they were old threads. Any ideas?

 

[Timfish]

I'd say they were molts, just the old exoskelton. SOme crustaceans have pretty thick exoskeletons and their molts can be mistaken for a dead body.

 

[shakacuz]

I'd say they were molts, just the old exoskelton. SOme crustaceans have pretty thick exoskeletons and their molts can be mistaken for a dead body.

i agree with this! many times before i woke up the next day or viewed the tank and noticed some "bodies" floating/moving around to then find out it was just a molt.

 

[WVNed]

Crabs grow by shedding their "skin". It looks exactly like a whole but dead crab appears in your tank.

 

[BillyBuckshot]

I appreciate it guys. So a molt will look like a complete crab. I was expecting just an outer shell, but y’all’s explanation would make sense.