I have a 55 gallon salt water aquarium with 4 blue green chromis in it. They were in the tank for about a week when one of them mysteriously disappeared I assumed a jumper because half of my tank was not covered for a time. Then I woke this morning to a tailless fish. Their only other tank mates and the suspects are:
A mated pair of coral banded shrimp
A mysterious shrimp that came in on the rocks that we think is a two claw cave shrimp
One hitch hiker crab of about 2 inches

the cut was very clean so the two brittle stars are not likely suspects


the crab has been isolated in a tank until a new home can be found. The blue green chromis that lost its tail is in a hospital tank... eating but injured

care for the chromis?
suggestions on who dunnit?

You sure the mysterious shrimp is not a mantis shrimp? If it is that's your problem.

Definitely not a mantis shrimp I have already researched this
Update:
the amputee fish has died
there have been no more killings

so it looks like the problem has solved its self