Lost my first red crab

Hi,

I lost a red crab last night.

I don't know why, all I can say is that it was out on my "island" all
day yesterday and looked alright, last night he was under it.

The only difference in the tank apart the water changes and the added
1/4 teaspoon aquarium salt, was that I installed the moonlight system.
But the light does not reach the "island" which stays dark.

I am sad. The only thing that I noticed unusual was that the crab had
lost two legs. Don't know how long tough.

This the problem with fish, they die and leave no clues as to why.

I decided to buy a bottle of Kent marine Iodine, mainly to help my
shrimps, hopefully it will help the crabs too.

Now I need to get a companion for my crab.