Dealing with a predator in a reef

[AngryTriGGer]

Not too sure exactly how I should deal with this as I'm somewhat new to marine tank keeping, (with in the last year and a half.) I've recently lost 3 fish, Mandarin dragonet, Lawnmower blenny, and now my Firefish. I'm pretty sure it's a predator of some sort as I have been hearing a clicking in my tank, usually after the lights go out. I have a 46 bow with about 60lbs of rock. I also have a 55 fowlr with a Dragon wrasse, Picasso trigger, Valentini all about 2-2 1/2". I also just got a 5" Niger trigger from a bud. Yes I know the 55 is too small as these fish are going to get big and I plan on upgrading. The Niger was in a 33 but thats a whole other story, and I figure I'm doing him a favour by giving him an extra foot of swimming room for now. Anyhow I'm wondering if I removed the rock work from my reef, as I'm unable to pin point which rock this predator may be in, and placed it in my fowlr, would my predators do the work on the predator living in my reef rock? I do know by doing so I will more than likely lose all my brittle stars, speghetti worms, etc. but I'm willing to do this in order to save my fish. Thanks for your time.

[i have crabs]

dragon wrasse would be my first guess, clicking is probably a pistol shrimp and even if its a mantis fish are not usually the fist thing to go missing

[fdiddy]

the dragon wrasse is in a different tank - that's my understanding anyways.

[AngryTriGGer]

Yes the dragon wrasse is in the fowlr. The missing fish are from the reef. Something in there is murdering my fish. They have all been fine in my reef for the last year or so. Side note, my firefish must have decided to "sleep in." Couldn't find him this morning and he wasn't in his home when I looked. But 2 fish in a month plus one fireshrimp and one cleaner also MIA tells me that something unfriendly is in there. Just wanna know if I transferred rock to my triggers if they would take care of whatever it may be?

[0sprey]

That depends on what it is.
You might want to try trapping it. Mantis Shrimp and larger predatory crabs can both be trapped.

[untamed]

Well...my opinion is that it is unlikely that your fish are being killed by a crab or mantis. Probably just a run of bad luck or something not optimum about the tank.

How long have you had these fish? (The one's that didn't make it)

[AngryTriGGer]

I had the lawnmower for about 1 1/2 years and the dragonet was about 1 yr. Got it super skinny and it was thriving in my tank. Getting very fat. I have a huge pod population. They were both very healthy. Reason why I think someting is preying on them is that I've been hearing a clicking sound lately and louder then hermit or snail shells on the glass. 3-4 clicks, pause, 3-4 more. Seems to be the back of the tank where it comes from and I cannot really see back there as I have a fair bit of rock in there. All water peramiters are within reason. Regular water changes. But like I said I'm still kinda new to the hobby so I'm open to suggestions and input. I've also been thinking of aquascaping both tanks again so thats why I ask if my predators will take care of a murderous crab or shrimp.

[Johnny Reefer]

.... Anyhow I'm wondering if I removed the rock work from my reef, as I'm unable to pin point which rock this predator may be in, and placed it in my fowlr, would my predators do the work on the predator living in my reef rock? ....
I've had a Pistol Shrimp in my FOWLR for over 2 years now. I have/had a Pink Tail Trigger, Blue Chin Trigger, Niger Trigger, Humuhumu Trigger, Blue Ring Angel, Bursa Trigger (RIP), and Clown Trigger (RIP). The Pistol is still there. If it's a crab you have...maybe. But then, how will you know when they've dealt with it?

[AngryTriGGer]

But then, how will you know when they've dealt with it?

Good question. Never thought of that and that is why I'm here asking you all for some input. I just assumed that triggers, wrasse, and puffers enjoyed shrimp/crab dinners as much as I do.

[Johnny Reefer]

.... I just assumed that triggers, wrasse, and puffers enjoyed shrimp/crab dinners as much as I do.
Regarding my Pistol....I'm sure my Triggers would enjoy chowing down on it....if they could get it. In other words, I think Pistols are more elusive than crabs. That's why I say "maybe" to crabs. I have a hunch my FOWLR is crab free. Not sure. It's been awhile since I looked at the tank at night with a flashlight.

[tang daddy]

Clicking could mean a mantis but it could also mean a pistol either way if it was a mantis you'd never fing it unless you actually saw it hiding in the rock to guess which rock would be like having a bunch of keys like 20 and 1 car.

Mantis are really smart when they hide they cut a rock and stick it snug to the entrance of their hole making you think that nothing was there.

Baby mantis can grow to a good size but would take awhile to be big.

You could try baiting the culprit with a piece of smelly prawn at night in a bottle turned on its side and a blue led shinning at the bottle sitting waiting.

Your lawn mower blenney sits on rocks so quite possible it could've gotten picked off, the mandrin was eating pods, I know you have alot of pods however a mandrin could clean shop in a month, I know my pseudo did it in 3 days. Unless the mandrin was eating brine or mysis and really fat he could have died of hunger or maybe even cyanide as 90 odd % are caught with cyanide and the rest probally speared.

If the clicks are so loud you can hear them from the other room it very well is a mantis.

[AngryTriGGer]

So I assume my best option would be to try and catch whatever may be the culprit. As far as the dragonet goes, I know it didn't decimate my pod population as i feed my tank small pellets once a day and the pods come out in huge numbers, even when the mandrin was in there. Like I said, it was fat and I had it about year. Cyanide maybe, don't know what the effects are long term..... but the clicking is there after lights out and i can hear it from other rooms in the house.

[tang daddy]

then I would bait it first I would try doing it in the rock work with a small bottle and something smelly maybe leave it overnight and check in the morning. If it's gone then repeat but only this time watching and if you get tired no problem just check again the next day. If it's gone again I would do it again and really watch. Remember mantis are smart but we are smarter always place the food in bottle the same place, once it gets familiar with the bottle it will think the bottle is food and then at that time you can try to find it's home.

Alternatively if you know forsure it's a mantis place the bottle right side up as it will take hime more time to escape, put a few rocks in the bottle and the food underneath it so it will have to fight for it's food, also tie a string to the bottle and hold onto it so you can yank it out when the bugger is in there.

[AngryTriGGer]

Funny you mention a pop bottle trap as I was just reading about them and it sounds like a plan. So first I must purchase a pop, some "stinky" seafood, and a fishing I will go. Thanks for the advice.

[tang daddy]

if you catch a mantis please make sure it goes to a good home. Oh and take some pics to share with all of us.

[Hartjl]

I had the exact same thing in my tank; the clicking, the shrimp and fish suddenly missing, etc. I tried the bottle trap method with no luck, my mantis was just to smart. At night I could watch by the moon lights and see him approach the bottle, but he would never go into it. However, the trap did bait him out of his cave so that I could see which rock he had tunnelled into (the one on the bottom of the reef of course). His hole was covered with a perfectly shaped rock to disguise the hole. I ended up pulling the rock out of the tank in the daytime when I knew he would be in it and chipping the openning wider with a chisel. Even with the hole open I could not easily get him out and had to pry him out with a screwdriver then chase him across the floor of my fish room.
Oh yeah, watch your fingers. The way he attacked the screwdriver I'm sure glad it wasn't a finger.

[muck]

Welcome to Canreef Hartjl!! :mrgreen:

[freddy]

I'm new to canreef,your problem might be a crab,lost a sixline wrasse,clown@ a yellow watchman gobie,didn't know what it was,till I saw a crab about the size of a quarter eating him for lunch.Got rid of the crab,no problems.Didn't know I had a crab in my tank till then,hitchhiker on live rock I guess.

[trilinearmipmap]

If you're pretty sure it's a mantis or crab then if you don't have a lot of corals encrusted on your rock you could try dipping the rock, either a hypersalinity dip or a brief FW dip, especially if you have a good idea which rock the critter is hiding in.

I've had a clicking in the back of my tank since I set the tank up 4 or 5 years ago, never lost any fish to it and never saw any mantis. In the first year I trapped out 10 or 15 crabs but whatever is making the clicking never went into the trap.