Without a trace?...

[Mue66]

I have a tank where fish keep disappearing. The tank is a Fiji Cube 38 Peninsula. It is a six month old mixed reef tank with minimalist Aquascape. The first fish to vanish was a 1” Darwin clown fish when the tank was 1 month old. The only other inhabitants at the time were a blue leg hermit and another juvenile clownfish of the same size. I replaced the missing clown with another Darwin a month later. The last of the original clown pair vanished shortly after. With only the replacement Darwin as a tank mate. It is five months later, the clown is re-paired with another juvi. But I come home to find one of my two Banggai’s gone under the same circumstances.
the tank is an open top (I will be changing that, my irresponsibility). I have small apartment, I have searched the surrounding flooring, the back AIO compartment (haven’t dismantled it yet though) without any evidence found.
Initially, my gut feeling was that they jumped, but these are tiny fish and certainly would appear within the search radius. I would imagine some trace of fish would be found if they were being eaten, there are only the aforementioned fish and trochus and Florida ceriths, 2 small nems and SPS/lps. A nem could be the culprit now, but was not present for the first two. Any ideas?
* I will be assembling a mesh top

 

[Shaun_in_Cali]

I had a firefish disappear. No idea what happened.

Did you use dry rock or live?

 

[Boonz28]

I’ve had a few fish vanish without a trace, the tanks were started with dry rock and had a top on them so no jumping and probably no pest hitchhikers. Also no chance that they were eaten by another fish.
I’ve seen fish that were in bad shape wedge themselves into something so they don’t have to exert energy fighting the current of open water, I guess it gives them some rest.
My theory is that sometimes when it’s a fish’s time to die they wedge themselves down into a rock somewhere so that they can die in peace and then you never find them. They eventually just decay and get consumed by your cleanup crew.

 

[Boonz28]

This may not be the case in your tank though. It could definitely be something eating them. And if not then it sounds like something (water chemistry, stray electrical current, disease, etc) is killing a lot of your fish and you need to get to the bottom of that

 

[Letterkenny]

I have a missing wrasse currently in my 130 with a lid. I’m trying to decide when it has been enough time to call it and get a new one. Happened to me on an older tank with a fire fish and when I was breaking down the tank I ended up finding it alive months later!

 

[Mue66]

I had a firefish disappear. No idea what happened.

Did you use dry rock or live?

I cycled dry rock for several months. Not a fan of the bristleworms and some of the other bizarre organisms and pests haha.

 

[Mue66]

I’ve had a few fish vanish without a trace, the tanks were started with dry rock and had a top on them so no jumping and probably no pest hitchhikers. Also no chance that they were eaten by another fish.
I’ve seen fish that were in bad shape wedge themselves into something so they don’t have to exert energy fighting the current of open water, I guess it gives them some rest.
My theory is that sometimes when it’s a fish’s time to die they wedge themselves down into a rock somewhere so that they can die in peace and then you never find them. They eventually just decay and get consumed by your cleanup crew.

Thanks. I’ll try to look in the rock work also. It’s a pretty minimalistic scape so not too many places to hide. It is bizarre as the fish are all juveniles and somewhat small in size. I’ve looked down the compartments of the AIO with a flashlight. No signs of anything, but I will try to disassemble for a better look to be safe.

 

[Chibils]

I've had fish disappear for months at a time before and then reappear without warning. Couldn't say what they were doing. I also had a yellow watchman goby go overflow surfing. He lived in my fuge under a ball of chaeto and in some rubble for a year or two before I discovered him - I was certain he was long gone. Fish can be cryptic like that, but it sounds like you don't have the same hiding spots and poor maintenance that my first tank was plagued with ... :)