Couldn't identify the culprit!?

[loonz]

About 2 weeks ago I lost my entire fish population to a suspect sea cucumber. I think it died and my fishes consumed it, and were lying everywhere motionless when I got home. I only found pieces of white flesh floating about it the tank and assumed it must have been the cuke,since all the fishes' bodies were in tact.

Anyway, I tested the water and ammonia proved undetectable both before and after a huge water change. I left the tank running on empty(is that how this phrase is used??) for a while and corals looked better than ever - possibly due to the lowered nitrate level and water change. I added 2 shrimps 2 days ago - a blood shrimp and a cleaner shrimp and made sure they were acclimatized and even fed properly before releasing them into the uninhabited tank save for some corals and LR. Yesterday I came home to a dead cleaner and a missing blood shrimp...I am most disheartened..The water parameters are near perfect I believe. And I have not heard anything that might resembled a mantis for many months. I caught one a few months back but it did not made any noise or killed any inhabitants then.

I have no idea what killed my shrimps....and am terrified of adding anythign to the tank now. What choices do I havE? Am I destined to keep a tank of corals and no fishes/shrimps ??

Are there any silent predators out there that I or any aquarists should know about???I'd at least feel a little comforted if I know of any usual suspects....I'd be thankful for any inputs, thanks...

 

[danmhippo]

If we assume there are chemical compounds still lingering in the water, try add a bag of charcoal, and replace everyweek for 3 weeks. Place the bag in high-flow area so the water must be in contact with carbon before leaving the charcoal bag.

Also blow out any detritus or animal tissues that may be trapped somewhere within the LR.

Also, do you have a refugium with caulerpa growing? Caulerpa is a good absorbant and can be removed when overgrown.

 

[loonz]

Chemipure was replaced on the day I made the huge water change. That was about 1.5 weeks back. I also stuffed 2 pieces of polyfilter into the canister.

I dont have a refugium. Somehow I dont think believe it is chemicals killing my inhabitants...cos all the snails are ok..there's about 10 of them visible at any one time. Are snails immune to certain toxins??

Anyway I am thinking of trying another shrimp, this time not releasing it but keeping it in a cage of some sort, to determine if it is really the water that's doing the killing... u think?

 

[danmhippo]

Good Idea.

 

[Anonymous]

If you believe their is a chance that their is a creature, mantis or other, that is killing your fish and shrimp, try adding a small octopus. It WILL eat any invertabrete (or fish for that matter) that is in the tank. I would only try this if you are 100% sure that there is no problem with your water, otherwise you will have a dead octopus. Some LFS's will sell you an octopus with the understanding that you will be returning shortly for a 50% refund of the original ourchase price. And you'll enjoy the octopus for a few days as they are interesting creatures in their own right!