BioCube 30gal Missing Fish - Case of the Disappearing Fish

[Charra]

I have had a biocube 30gal for about 5 years now and my fish disappear consistently. I have never found one even when I know it was there earlier in the day but isn't later in the day. I have looked up in the hood, the back in all 3 compartments, in the sand, under the rocks and have even torn my tank apart looking and it's like they just vanished! It drives me crazy and I wish I knew where they were disappearing to. I only have 1 cleaner shrimp, a tiger conch (new), an urchin (also new) and 2 very small blue hermit crabs in there so I know it is not them that are eating the fish that fast. The Urchin is literally brand new so it definitely is not him and the conch is only a couple of months old. This has been happening for YEARS. My water quality is near perfect but even if it wasn't I would at least be able to find the body. The tank has a hood so they can't jump out but even so I have searched the carpet, and all around the tank. There is literally no explanation of where they have gone.

I am down to one fish and I am not putting any more into this tank until I find out what is happening to them.

If anyone else has heard of this before and knows why this is happening please share! Pics attached.

P.s. I also have a 90gal saltwater tank and have had both for almost 6 years. I am pretty experienced in saltwater tanks.

 

[andrewey]

By any chance, have you sifted through your sand and rock to confirm you don't have anything bad like a bobbit worm or some other fish eater?