How to Find and Kill Evil Hitchhikers

[Pier Pressure]

Last weekend when the tank lights went out at eleven, all fish, inverts and corals were doing fine. The fish were eating like pigs as usual, very active.

By nine-thirty the next morning, five of my fish and three of my shrimp were dead. Now you may start thinking water quality, but the inverts, anemones, etc. are fine and water tests are good, too.

A couple days later, my firefish came out of hiding in the rocks. He is still very skittish but spending more time outside of his rock than he was originally.

Long story short - I think I may have a hitchhiker(s) that is evil and killing my livestock. How do I catch it/them? Especially if there is more than one.

The tank is only a 28 gallon but there are about 30 pounds of live rock in there. Tips or tricks most appreciated.

[seashells]

Ye olde bottle trap. I only caught one that way but hey its a start!!

[Dragonsteeth]

What could this creature be that seeks and destroys several fish overnight?

[Pier Pressure]

General Consensus seems to be some kind of evil crab. Anybody got a link on how to do this bottle trap thingy?

I am fairly new to salt - less than six months in so far.

Water quality could not be the issue because my inverts (other than the shrimp) were fine. Spike would have to be crazy-large for ammonia to kill in 9.5 hours, too.

Plus the firefish is okay. It took him two days to come out of his rock and he is still very skittish. He must he hiding from something.

[Der_Iron_Chef]

Yeah, try the old bottle trick. Sometimes it works, sometimes it doesn't. Here's an image I found:

[Pier Pressure]

Thanks, Drew. I guess some of my hermit crabs will get trapped as well but I can always let those go. Once I get the killer(s) I shall happily fork them to death. I am not usually much for that sort of thing - but this is now about vengence for my dead livestock!

[Murminator]

Originally Posted by Dragonsteeth

What could this creature be that seeks and destroys several fish overnight?

This was my question also I been trying to help her on AA also. I cannot see a crab killing a blue sided wrasse, royal gramma, clown, damsel, midas blenny, and 3 shrimp in one night with no visible scars.
I think it is biological the tank does contain 2 sea apples and 2 anemones I think the apples got stressed released something(poison) into the water killed everything and since it was such a small space it was quickly skimmed out by morning
......but I have recently fallin off a turnip truck ....so I been told

[Pier Pressure]

Murray according to the research I have done on sea apples, if they release the toxin they are done. They blow up to volleyball size and die after the release of the toxin. Elite has sea apples in many of their tanks, and I was informed that they have seen feeder tentacles pulled off and a sea apple actually cut in half and in neither case did they release the toxin.

The green bubble tip anemone hosts a white caribbean crab who is still alive and fine, and the white sebae is located right next to my open brain and xenia and they are fine, too.

I could see the poison thing being a reality if everything did indeed die. But the hermit crabs, emerald crab, sea apples, anemones, etc. are all fine. Why didn't they die, too?

Also what about that crazy firefish? How come he is still alive and fine, though appears skittish as stated?

I have no idea what could kill all those creatures overnight but if I find anything I will certainly let you know.

I just had a thought - I bought a gi-normous brittle star (purple and black in colour) a few months ago. He disappeared into the rocks and we laughed and laughed at having spent $35 on a creature we have only seen once.

Well, I managed to catch a glimpse of one of his arms yesterday and he is huge. Could one of those kill the creatures if so inclined? I am going to look that up right away.

Thing is - that brittle star has been in there for months. Why kill so suddenly? And isn't it a coincidence that I put new coral frags and a gsp rock in that day, and suddenly everybody is dead less than twelve hours later?

Thank you for all of your help, guys, here and on AA. It will drive me crazy until I figure it out. And I do not want to put more livestock into a death zone without knowing what killed everybody.

[seashells]

I have lost crabs, snails, a clown, and now my Mandarin has slices in its tail fin. Frustration!! Can't find the culprit!

[dunl]

What kind of marks are on the fish? If nothing, it's not a crab, mantis, or brittle star.