Something is out there

[rfs0008]

My boss and I just started a saltwater aquarium. We bought live rock and set up the tank. A week later we bought 4 green chromis. 2 days later, one of our fish was missing his tail and the end was red and bloody. We called the aquarum store when got 2 of the fish and the live rock from and they suggested it was a mantis shrimp. The fish died. The next day another fish had a large verticle laceration on his body which progressively got worse, and it later died. We came in at night to watch for this shrimp. We found one and killed it. We then soaked all of the live rock in carbonated water for 30 minutes and found another one. We sifted through all of the live pucca shells and found nothing so we assumed we had gotten them all. We replaced the 2 fish that had died and a day later one of the fish that we replaced has a laceration like the second fish. Does anyone have any suggestions about how we can catch these and if you think there are more. Could they be anything else? The PH is 8, ammonia mostly undetectable, nitrites are less than .25, and nitrates at 10ppm. We have a 30 gallon tank. Any help would be much appreciated

[Max]

Do an archives search for mantis traps that will probably help out quite a bit. Umh, well something just a bit more important. It doesn't sound like your tank has cycled your ammonia and nitrite levels shoudl be 0 on home quality test kits. What did you use to cycle you tank uncured live rock , cocktail shrimp or the chromis? If you are using the chromis I wouldn't add any more until after the cycle is done. The tank is still building up it's bacteria population and all these new critters are just sort of adding fuel to the fire. Also when it's done you're going to have a tank cycled for 4 chromis and anything else you add will trigger a mini cycle. I'd remove the fish and let the live rock ,"if it's not cured ", finish the cycle or I'd throw in a cock tail shrimp or two and let them rot away and when your ammonia and nitrites are at 0 you are good to go. Oh yeah nearly forgot WELCOME TO AQUARIA CENTRAL!!!
hth
Chris
:D

[rfs0008]

Thanks for the advice. We came to the office last night and set one of the bottle traps I made and sat there with a red light. We didn't see anything. When we got here this morning nothing had been touched. Even the fish that died over night. My boss seems to think that it might be the two original chromis. They have gone through 2 sets of fish. Each time we added a fish we changed the scenery around like the book said to head off some territorial urges. Only the 1st two remain and have never been injured. My boss did some research and found some sites where people would put in green chromis and would come up with injured animals. We chose them because they are supposed to be peaceful. The person at our fish store said that usually the mantis shrimp will eat them and not just mortally wound them. Have you had any experience with this her heard of anyone who has?