the case of the missing fish

[Nyxe]

Hello everyone.

As the subject states, I have missing fish! I have 2 clowns, a pink spotted watchman goby, 3 firefish, a scooter blenny, and a purple stripe pseudochromis.

Out of the first batch of fish introduced to my tank (goby, clowns, pseudo) only the goby and clowns were seen in the tank. The pseudo hasn't been seen since the minute he was netted into the tank.

Out of the second batch of fish (3 firefish and scooter blenny), all 3 firefish and blenny were present and accounted for on the first day. The second day, only two firefish and the blenny were seen. On the third day, only one firefish was seen from that day forth.

A week or so has passed since the disappearance of the two firefish and blenny. Four out of eight fish missing is a rather large count.

So today we spent our evening taking our LR and corals out of the tank and into buckets to search for the missing fish. We took out all the live rock and corals and our snails. We shook the live rock under water to see if any fish came darting out. Nothing. We sifted through the sand (and only succeeded in startling our goby). We saw a speck of red in the sand. Turns out it was the front part of our one scarlet hermit crab. Something tore it in half and ate it? We found the scarlet's shell, empty.

Our search turned up nothing except the dead hermit crab. No dead fish, no live missing fish, nothing.

So where'd our fish go? We have a glass lid on the top so there couldn't have been any jumpers. Our overflow box is empty. There are no fish in our sump.

Do we have a mystery fish-eater in our tank? What could it be? Our live rock seemed uninhabited by nefarious creatures when we took them out. No weird crabs or creatures have been sighted.

But we do have a dead hermit crab, a dead snail, and four missing fish. What's going on?

We haven't heard any "popping" noises that would suggest a mantis. Never saw a hitchhiker crab. The only hitchhikers we ever saw were small bristleworms and stomatella snails.

Where'd our fish go?

Inhabitants:
4 trochus snails
5 astrea snails
1 nassarius
2 ocellaris clownfish
1 pink spotted watchman goby
1 firefish

Missing inhabitants:
2 firefish
1 scooter blenny
1 purple stripe pseudochromis

Dead inhabitants:
1 trochus snail
1 scarlet hermit crab

Corals:
green star polyps
toadstool
mushrooms

tank info:
46g bowfront
11g sump
1.024 salinity
79 F temp
63lbs LR (tonga/fiji)
80lbs live sand

water parameters (as of last night):
ammonia 20
nitrates 15

I think I'm going through mini-cycle? My ammonia was stable at 0 prior to the missing fish mystery, and my nitrates at 5.

I'm going crazy. Where did my fish go? Do I have a mystery fish-eating hitchhiker? Please help!

[Deb91]

I hope is is not a mantis shrimp. I googled Mantis shrimp video last night,because someone was having trouble with getting one out last night. The way you described that crab brings back the chills I had last night. Do me a favor and google mantis shrimp video,nothing else in your tank could do that especially the way you searched so theroelly (sp)!

[Sk8r]

I hate to say, but get a flashlight and check behind the tank. Jumpers frequently get out.

[Nyxe]

The back of the tank is clear of fish. I made sure to check. I don't think it's a mantis shrimp, but just in case I'll lurk after lights out to see if I hear or see anything out of the ordinary.

Other than suicide jumping out of the tank and a murderous mantis shrimp, what else could be the answer to the case of the missing shrimp? xD

[rick12]

how long have you had your tank set-up and the LR installed. im the guy who spotted my mantis shrimp after months of set-up. you would be amazed at how well they hide and how fast they move. do check out the video

[zotzer]

If you have crabs in the tank, they'd dispatch a dead fish very very quickly until there was no trace of it.

Tell us about your acclimation process when adding new fish....
Tracy

[snorvich]

Well the ammonia level is suspicious. Firefish often do not get along together unless you happen to luck into a mated pair. They are also notorious jumpers. I don't know the physical layout of your tank, but are they able to jump into the overflow?

[Nyxe]

The only crab I put into the tank is the scarlet hermit we found dead today.

All fish were drip acclimated over an hour or more.

The LFS said that firefish do better in groups so we got 3 at the same time (the were all in the same tank at the LFS). The one remaining firefish does look a bit ragged. It's swimming around, and I haven't noticed it go into any bolt-hole as of yet.

We bought a glass top for the tank before we got any fish (since I've had a firefish before in a previous nano tank I'd owned). The back plastic part of the glass top was cut to go around the overflow, return, and various power lines, but it is a tight fit. The fish would have had to be Houdini to jump into the overflow or squeeze out of the tank.

I guess I'll try a mantis trap, although I'm not really certain there's a mantis in there. It wouldn't help to try though, right?

And I'll do some lights-out spying as well. Maybe I'll spot whatever's causing my disappearing fish.

[Deb91]

There is nothing in there that can explain the way that crab was tore up to me except for the mantis shrimp. Did you watch a least the first video? All those fish missing without a trace that fast. I would be heartbroken which I'm sure you are.I hope you find out soon what it is.Best of luck in finding the culprit! By the way I forgot to say

[welcome]