Predator in my tank. HELP!!!!

[Toadfish]

I guess I have been in denial since I found one of my emerald crabs claw, and seem to be one emerald short. Ok, now one of my clams took it in the gland, and died today. On top of all of this, I have not seen my peppermint shrimp in 3 days. I have stayed up late the last three nights, with a red filter on my flash light and nothing. I haven't seen any predatory crbs or shrimp. My hermit population has also slowly declined. I am at an impass. I don't want to tear into my tank w/o knowing what I'm looking for. My cleaners, 1 emerald and fish are still alive. Does anyone have any suggestions? Should I just rip into the tank not knowing which hole it, whatever it is...lurking. Need some advice, please help!

[gregt]

Are you certain the problem is predation? Have you checked all your water parameters?

[Toadfish]

Yes...all water parameters are excellent. The way the bysal gland was severed on the clam leads me to believe it's a predator. I posted some pics of it on the clam board.

[gregt]

Man, I'm not sure what I'd do without the slightest idea what it may be. The reason I'm leaning against predation is that it would take an awfully big something to warrant that much carnage. Generally a predator will only kill one thing at a time and that lasts for a few days or a week or more in most cases.

Any chance a toxin got in the tank? Copper, etc....

I'm just guessing....

[Toadfish]

I guess there's always a chance of that, although unlikely. This has transpired over a 2 week period. That's when I found the emerald crab.

[Geoff]

maybe try baiting somehow. like put a piece of shrimp in a small bottle. hopefully the culprit will show itself trying to get to the shrimp. how big is the tank? just wondering if the tank was big enough that i could be localized to a certain area. if the tank is under 2-3 feet in length, it is difficult to do localization.

hermit pops dend to slowly decline. they seem to only live a couple of years anyway.

G~

[gregt]

After sleeping on it, I'm still doubting that any predator could do that much damage in only two weeks. It takes a lot of energy for these guys to kill another creature, and the types of things that have died are so varied, there aren't many things that would want to eat all that kind of stuff.

I still think you have another problem. Perhaps you have a predator that caused one or two of the deaths, but I would keep an open mind to other possibilities....

[Mafiaman]

Any new live rock? There are two reasons I ask.
One, In transport things get hungry
Two,(and this happend to me) I had two Viper eels pop out of some new rock I got in Tampa and the killed what got into there sights. They were not much bigger than earth worms

[sfletch3]

Have been told that if you take a glass that is smooth sided (inside) and lean it at a 45 degree angle in the tank. (Maybe against some LR), bait it with some food, the culprit will sometimes climb into the glass for the food, and not be able to climb back out. Then just check the glass each morning and re-bait if necessary. I'm not saying this works everytime, but it doesn't cost anything and is reef friendly.

[tdwyatt]

Hmmmm...


This sounds more like an issue with salinity, either too low or rapidly fluctuating, especially if it is restricted to your crustaceans (may affect them to the benthos level as well). How do you do your top-off, and how big is your tank? Clams in particular are very sensitive to changing salinities and will detach their byssal threads under those circumstances... If you use auto-top-off, do you track how much water it actually uses? Sometimes this is the only means of tracking a malfunctioning Auto-top-off mechanism...

I just don't think that a predator along the lines of what would be lurking in a home system and undetectable would do this much to your tank (I concur with GregT on this), although it would be good to set pout some mantis traps in case you have a population of them...

good luck, hth

[Toadfish]

salinity stays at 1.025, but I do top off daily. I do not have an auto top system. I guess there could be some shifts, but not to drastic b/c I top off daily. BTW 75g tank 30g sump.

[toddrudolph]

Does the tank have a ground probe on it. I have watched a similer thing happen inverts, fish slowly die of from stray electricity. Crabs are pretty sensitive to this. Just another option out of the ordenary that could cause this sort of thing to go on in a tank.

[Toadfish]

Yes...there is a ground probe in the tank