please help, three fish dead

[aklein14]

30 gal live rock aquarium, i have hermits, snails, emperor crab, porcelain crab and strawberry crab. I recently got an urchin and have noticed a large 6-12 inch bristle worm in the tank. I had 2. Clowns 1 tail spot and a goby. In the past week i have lost two fish that look healthy found on the sand bed partially eaten. I still have not found any remains of my clown that went missing. Remaining clown looks healthy and acting normal. Ph, calcium, nitrate and Phosphate are all good.

What other parameters should i check or what should i remove from the tank?

I plan to do a 5 gal water change tomorrow

Thanks for the help.

 

[H2Ohio]

Sorry to hear anyone who runs into this kind of trouble. You are likely to get better responses if you include the size of your tank, how old it is, how long were all these fish living fine in the tank and have you tested for ammonia.

 

[mike007]

If you can provide us your water parameters such as ammonia, nitrates , etc. Did you quarantine these fish? How long has this tank been setup?

 

[deerhunter06]

how bout a pic of this bristleworm too.

+ 1 on ammonia levels. how long have you been set up?

 

[afamousjohnson]

Ya if it's a new tank you found the prob. If it's been set up maybe look for a fish killing pest If water tests out

 

[glb]

Water changes are always a first response to stuff like this. They can't do any harm (unless they're too big).

 

[Humblefish]

Porcelain crabs are generally fine; I don't know anything about emperor crabs; but strawberry crabs are known fish eaters. All crabs are opportunistic feeders and nocturnal by nature. If a hungry crab happens upon a sleeping fish at night, they will usually try to take it down. It's just food to them.

 

[Reefing Madness]

When was the last fish introduced? He may have brought something in with him, something not good to have.

 

[BlueDiamondDiscus]

The starwberry crab are the killers as well.
The clowns are hardy and they haven't the reason to die.Are they bought as fry from your local breede?Just a question.