case of the mysterious disappearing Bangaii Cardinals

[pontius]

I've had a pair of Bangaii for well over a year. now suddenly, they've disappeared without a trace. I checked around to make sure that didn't jump, they didn't. all water parameters are normal, and I don't have anything that is predatory in my tank.
now here's something wierd: 2 weeks ago, I bought a second pair of Bangaii (for a total of four). they were full grown and had been at my lfs for weeks, apparently healthy. I put them in, and they were both dead within a day. I was po'd, but I didn't think much of it one way or another. but now these two are gone, and I don't get it. they have both been very healthy for over a year with healthy appettites, they've just disappeared.
could it be that I've stumbled onto a disease that is specific to Bangaii cardinals, and the 2 new ones infected the established ones???? if not, what else could it be? all other fish are apparently healthy and normal.

 

[escape2thewater]

I dont have an answer for you but only my story about a similar disappearance I have in my reef. I have had 2 full sized yellow tangs dissappear in my tank within the past 8 months. I had one tang for about a year then back around last christmass it disappearrd. Without a trace. I just figured oh well, maybe it got sick and died in the rocks somewhere then got eaten by everything else. Well about 6 months or so later I bought another one. It disappeared about 3 weeks after being in the tank. Just like yours, eating well and in good shape. I think we both must have some type of predator in our tanks that maybe only comes out at night. Ive been looking for mine with a flashlight & red lens a couple times at night with lights out. Ive had no luck yet but something HAS to be killing these fish. You most likely have the same problem. Try looking at your tank at night with a red light to see what appears. Maybe a big bristle worm, Some wierd crab, or big serpant star could do this? Good luck with yours, I know how frustrating it is to have this stupid problem!
EScape

 

[pontius]

well, I haven't put any new rock or anything in since I set the tank up over 14 months ago, so I definitely don't think it's a hitchiker that has suddenly decided to strike twice in one day.
I do have a serpent star, but I have never seen it act aggresively, I don't see how it would ambush these fish.
I also have a large condi anemone. don't know if these would eat fish, but it hasn't moved from it's rock in over a year, so the fish would've had to have swam directly into it.

 

[escape2thewater]

I havent put any new LR in my tank in over a year either. What kind of serpent star do you have? How big is it? I have heard of green serpents eating large fish. I have a red serpent in my tank but its very small only like 4 inches across so I doubt it ate a yellow tang that was bigger then it but something ate it. Just like your fish, mine did not jump out. They have just disappeared. Do you have a DSB? How much LR? It is possible maybe a predator has grown big enough over thelast 14 months to do this?
EScape

 

[drea]

that is crazy!!!!!!!!

 

[pontius]

Escape, the serpent star is a green one, from one arm tip to the other, I would say maybe 5-6 inches span across. but all it pretty much does is hang out under the rocks, while the bangaii are pretty much in the mid-water column, so I don't see how it could have gotten them if it had wanted to.
my tank is 72 gallons with approx 2.5 inch sandbed and about 140 pounds of live rock.