Emerald crab or other predator?

[NatureNerd]

Ok, I have not lost a fish or shrimp in years. Now suddenly, things are gone. First a cleaner shrimp, two days later a second cleaner shrimp, and now my purple firefish. What is going on. All parameters are fine, tank and corals looking great but things are disappearing. I added a half dollar sized emerald crab about three weeks ago. Could this be the problem. Note that I have not seen this crab since the second shrimp disappeared also.


Stocking is: Small BT Tang, pair of Occ clowns, pair of neon gobies, dragon faced pipefish, tail spot blenny. Nothing that could eat a firefish.

Any ideas? I have not added live rock or anything else in over a year.

[NatureNerd]

Also tank has a lid so no carpet surfing explanation either.

[DrBegalke]

I doubt the emerald crab killed them. I've kept them in several tanks, usually a few per tank, and haven't had a problem.

Have you tested your parameters?

[rsl3]

I really do not think it would be the emerald crab. Try taking a flashlight after your lights have been off for a few hours and shine it in the tank and see if by chance you have any bristleworms. In the past I have heard people finding bristleworms to be eating their livestock with no knowledge they even had them. Best of luck!

[NatureNerd]

I tested and all water parameters are excellent and SPS's never looked better.

I often take a flashlight to my tank. It is fun to see the night crew at work. I have small red leg hermits, snails, and countless pods. And yes, I have always had bristleworms. I believe they usually only eat dead things. I can't imagine one eating a two inch long firefish or a mature cleaner shrimp. Unless they died first. Maybe I am wrong on this.

[divewsharks]

very few bristleworms normally found in our hobby are of any threat to your livestock; they are an important part of the cleanup crew.
While emeralds can on occasion not play nice (they are crabs, crabs or omnivore opportunists...) i don't think at the size you have, is of much threat.
where did your rock come from? you may have another hitchhiking crab in the tank that could be doing the damage.

[ojonas81]

I started to have the same issue a few weeks back. It has still not been resolved. I have a thread about it over at the invert forum.
http://www.reefcentral.com/forums/showthread.php?t=2119663
I have no clue on what is going on. Everything else in the tank looks pristine.

I don't think it is a bristle worm. At least the ones in my tank are way too slow for a shrimp or a fish.

[mph1]

A few days ago I noticed my cleaner shrimp missing a tail...like it had been chopped off cleanly. It was still alive and seemed healthy, just a bit slower. Yesterday I watched the emerald devour it. I didn't witness the intermediate events but it's not hard to imagine. The emerald I have is quite fast.

[davocean]

I would not really suspect the emerald, but I have heard of some bristles getting very large and becoming an issue.(I just pulled a 5" one for this reason, and they can get much bigger)
Sometimes over dosing iodine can cause stress on inverts, excessive molting causing death, not sure if you dose that.