killer cleaner shrimp?

[g. mcclean]

I know this has been discussed before but here I go again. I have lost another fish from my 46 gallon. Ammonia 0; nitrite 0; salinity 1.023; pH 8.2. In other words water parameters are fine. Two days before he went missing (a red sandhopper --blennie) I saw the shrimp on him on the bottom. The blennie spent a good deal of time on the bottom or perched on the rock work. We have also recently lost 2 green chromis. This shrimp is the same one I saw pick up a fairly large hermit and dump it out of its shell. It did not eat it. Is it possible that in its efforts to clean a fish it might injure it? I am extremely frustrated over the loss of fish for mysterious reasons. If I am doing something wrong I might be able to correct it but until I can uncover the problem I am at a loss. Any suggestions greatly appreciated.

[OrionGirl]

There are false cleaners that will nip bits of flesh, but usually not kill the fish. However, I would suspect something other than the shrimp--if the shrimp were hurting the fish, they would not hang around and tolerate it, they would swim off. Have you observed the tank at night? Many nasty hitch hikers will come out at night to do their dirty work, and the hapless cleaner is just doing it's job on the leftovers the next morning.

[mogurnda]

I have heard of cleaners taking pieces off of Tridacnid clams, but I find it hard to believe that a healthy fish could not escape one.

I still think that it may have more to do with a sick fish being more attractive or willing to be cleaned. How long had you owned the blenny?

[kreblak]

My cleaner shrimp has some strange tendencies as well, but he isn't killing anything. I did watch him pull an astrea snail off the glass, and pick at it, but that was one incident. Plus, I have no idea what the shrimp was doing in that case. The snail moved on afterwards.

I have to agree with Dave on this. True cleaner shrimp don't kill fish, but a sick or injured fish is likely to hang around a cleaner shrimp more often, making it appear as though the shrimp might be up to something.

Check your live rock after lights out with a flashlight, and see if you have any nasties that have made their way into your tank. After my Niger Trigger went missing, I started doing surprise inspections at night to try to find what happened. I have yet to find a culprit, but I have my suspicions.

[g. mcclean]

Dave, in response to your question we have had the blennie for several months (perhaps 3-4) The day before he went missing he was eating heartily as always. I will check the live rock for the next several nights. What exactly am I looking for? I would imagine it would have to be rather large to kill a fish.

[liquafaction]

Sometimes at night, I will inspect my tank with a small "under the sheets" light. It is amazing what goes on at night as I am sure you might know. Shrimp eyes reflect light, so they are easy to spot real quick. My pepermints eyes look like 2 freshly blown out match sticks when they reflect light.

[mogurnda]

Here's another lame grasp. Do you hear any clicking? Although a lot of people worry about mantis shrimp, I have heard reliable reports of pistol shrimp stunning and killing relatively large fish. Mine have always behaved, but a bottom dweller like a blenny might be particularly likely to stick its nose into a hole and be stunned.

[kreblak]

Pistol shrimp and mantis shrimp are always good cuplrits. I have yet to find any in my tank, but something took out my trigger. Oh, and G, like your blennie, my trigger had been doing fine for 4-5 months when he just disappeared one day. I still haven't figured out what happened.