Yellow Tail Blue Damsel

My damsel seems to be doing fine but is now missing part of tail fin. He's swimming and eating but can't understand what took his tail. I have 4 arrow crabs, 2 spotted cleaner shrimp. 1 peppermint shrimp, 1 turbo snail, a couple of small unknown crabs, 1 star, 2 flamingo tongue's and now a worm that came out of no where about 2 inches long with funny looking eyes, I'll try and post a pic. Any ideas?
Thanks

 

could have been one fo your cleaner shrimp went to clean him and held on by the fin.i would get ri of that worm asap until you can get a ID on him.he doesnt look friendly.

 

I have a new pic of my arrow crab trying to eat the worm, so I quess I don't have to worry about catching him. I never would have thought the cleaner shrimp would eat the tail of my damsel.

 

You just never know......

 

Could just as easily be one of your arrow crabs. They get very aggressive and will go after small fish. --- you may want to consider moving them along when they get bigger, if you are going to keep fish in same tank with them.