Are My Critters Escaping or Being Eaten?

cjpitt80

New member
OK,
So in the last 5 days I've had some disappearances. Current livestock is 1 black molly (hold over from cycling) a pair of ocellaris clowns, a banggai cardinalfish, and a clean up crew with trochus, nassarius, cerith snails and few other snails. I also have a skunk cleaner shrimp a Fire red cherry shrimp, 2 nickel size emerald crabs and 2 quarter size emeralds. The tank is about 98% covered with only the back 2in or so open. One side has the overflow so even less surface area is exposed

Up until 3 days ago I also had a Coral Banded Shrimp for about 2 months. Thur morning he was there, Fri evening, gone. I've never seen anything act aggressively to him. The emeralds don't seem to bother him or anything for that matter, they just go around picking on the rocks all day. He's molted 2x since I've had him and the exoskeleton remains in the tank about a day and a half (same thing for the fire shrimp). If he was attacked, I would think I would have seen a claw or something, but NOTHING. Checked all around the floor, behind the tank...no sign of him.

Last night I added 2 more slightly smaller banggais to the tank (after spending 2 weeks in QT). All looked well. No aggression with the established guy, one of the smaller ones even seemed to pair up with the existing one. Woke up this morning and.....of course. Same thing. Completely disappeared into the abyss. No sign. No fins floating around. No skin. No dried up fish on the carpet. NOTHING. ONLY the 2 smaller ones I added. The original one is in there looking completely fine and normal.

What the heck is going on here? Obviously, there are only two possibilities. They're getting out, or getting eaten right? With the coral banded shrimp, I can only think it would be the emerald crabs get together and actually "hunted" him down? I've never witnessed this and I'm pretty sure that's not their behavior as they are scavengers and opportunistic feeders. The CBS looked fine last I saw him. Had grown back one of his claws to almost regular size. Even still I find it hard to believe they could completely consume the body with no trace in that short time. When any of the shrimp molt, the exoskeleton remains for a couple days. For the fish, ONLY the 2 new ones are gone? They both decided to jump out or were both eaten in a 8hr period? Again I see no bodies anywhere. Nothing. Ugh. FRUSTRATING. What do you guys think actualy happened?

Also for any newbies if you have diamond watchman goby COVER your tank COMPLETELY. Those guys def jump and will find any tiny hole at the top of your 10gal QT tank near the filter and jump out. Eventhough they'll act like they stay only on the bottom and you'll never see them swim higher than the bottom 1/3 of the tank, they'll jump. But they'll land on the carpet and you can easily see what happeed to the't ask me how I know this...
 
What kind of rock? Live rock might have a hitch hiker you haven't seen yet. Mantis?

I used the Carribsea Life Rock (fake purple fry stuff). No hitchhikers. The CBS was about 3in body length about 6in total with antennae. He wasn't a lil guy... That's what's puzzling, I don't think anything could take him out even if they tried to. I've seen the crabs completely ignore him. Anyone know how long they can live outside the tank? Maybe he crawled over to the kitchen and croaked? And of course, still no sign of the new banggais.... Man, this sucks
 
Mantis would seem likely. It wouldn't hurt to set a trap. google soda bottle trap.

What's the smallest size mantis shrimp? Rather, what's the smallest that could take down a CBS? Also, it could completely consume it with no trace at all? No claws, no antenna, just disappeared. I googled it and I've certainly never seen anything like that in my tank and I don't have any broken shells from the other CUC. I'll do another super close check later to see if I see anything.
 
I had one. Never saw it even with close inspection. Just kept missing thing, like you. Set the trap, next morning there it was. I don't know how much rock work you have, but these critters hide in the smallest places where they can't be seen. They attack by surprise, not stalking. They wait for the prey to come by.
 
If you started with dry dead rock, there can't be a mantis. I've had lots of emerald crabs and a quarter sized one can take out a cbs. (body quarter sized excluding limbs) They tear it apart into pieces so it's not like a molt. ….remains will be hard to find....

your cbs seems pretty large......but the claws on the emerald are strong....


I once had 9 emeralds in a 10 gallon tank with other various crustaceans…..after 6 months or so only one emerald out of the 9 remained....the largest one.....he had a guilty smile on his face.....
 
Update

Update

Ok so after careful inspection I've found ONE of the Banggais. I guess he's still adjusting to the new environment. He's hiding in the rockwork in the very back. He looks healthy but doesn't eat so hopefully he'll adjust soon. Both the new cardinals were eating mysis in the QT. When I put them in the DT they seemed normal when I woke up they went in to hiding. I still can't find the other one, but I guess he's hiding somewhere in the rockwork also

No sign of the CBS. Also, there's no chance anything is in the plumbing. I have just one 1.5in pipe for the overflow, so something would have to swim AGAINST the current. The I have the reef synergy overflow and the teeth are too small for even a little peppermint shrimp to get thru. The emerald crabs a little smaller than a quarter actually. I guess those are the most likely culprit but would they actually ATTACK a CBS? I know they're mostly opportunistic and scavengers. The CBS had some size to him though and he's pretty quick when touched. Just observing him and the crabs, I'm not seeing them taking the CBS out. Like they'd have to chase and hunt him down, I've never seen any of the emeralds move faster than a snail...

Unless a mantis can come in as an egg or microscopic size on livestock, I'm pretty sure I don't have one. And what size would one have to be to take out a pretty big size CBS?
 
In my experience the key to keeping your emeralds from eating their tank mates is to feed them. They are voracious eaters and while that's great for cleanup, not so good for friends when they're hungry.
 
UPDATE!!
Well, found one of the other cardinals dead on the over flow :( I'm assuming the other died somewhere in the rocks and the emeralds took care of him.

I'm STILL stumped on the CBS. Again, he was pretty big size. They also can move pretty fast with that initial squirt they do. I've never seen any of the emeralds move that fast. There's also a decent size skunk cleaner in there and 2 smaller peppermint shrimp. I've never seen the emeralds go after anything large or lively. Has anyone ever seen an Emerald actively hunt and CHASE prey?? I ordered a replacement CBS and somehow neglected to see the size. He was TINY (maybe an inch total) and looked like he was having trouble acclimating . It was pretty clear what would happen to him when he went in the tank, and it did. One of the emeralds totally devoured him in maybe 5min. So I know it COULD happen, but I'm just really not sure with the size he was. and no other smaller inverts are missing. Anyway, I'll just have to head down to the LFS for a replacement. This has still got me stumped though...
 
Crustaceans often molt on arrival in a new tank. In molt, they are vulnerable, and hide. Or get eaten.
 
Crustaceans often molt on arrival in a new tank. In molt, they are vulnerable, and hide. Or get eaten.

Yeah, once I saw the size of the new one, it was clear he had NO chance. Still a little confused about the big guy though.
 
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