This thing killed my acro!!!

[uchiha]

This week, I noticed a little bleaching in my green a. humilis (?), I finally got around to taking out the colony, and inspecting it. I managed to find this really weird looking clear larval crab/shrimp thing stuck in the branches.

I believe this is what was eating my acro, but I would like to be sure that it WAS this and not something else, which may overtake my tank.

This is what I lost:


Here are pics of the 1cm shrimp looking thing:
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Any help will be greatly appreciated, as I mentioned above, I think it may be some sort of late-larval acro-eating crab???