Fish keep disappearing!

[Miami Reef]

Its a huge mystery and I have no clue what’s happening. Every time I add a new fish, it’s gone and there’s no evidence of the body. It’s been happening a lot lately.

I tried adding blue tangs 3 times and they all disappeared. I had a line wrasse and a white clownfish and 3 diamond gobies that all disappeared. I checked behind all the rocks and there’s no sign.

My current fish are a yellow tang, sailfin tang, foxface fish, a few percula clowns, fire fish, and spotted sweet lips.

As far as I see (I check on the tank a lot) I don’t see any aggression at all. No chasing or attacking either. The oldest fish in the tank is the yellow tang. I’ve had it for almost 10 years already. I was lucky to add the sailfin tang, because every other tang that I’ve added has disappeared.

 

[Scotty Buttons]

I think you have a monster hiding in your rock.

 

[Bob Ander]

There is a good chance that your tangs are picking on and killing you new fish. Tangs tend to not get along well especially once one is already established since they are very territorial. Your clean up crew is probably taking care of the body or it is getting stuck in or behind rocks. With 3 tangs I’m guessing your tank is fairly large which leaves a lot of space for a fish to go missing. How large is your tank and what other livestock do you have including corals?

 

[Sarah24!]

Hello,

I would agree with the above post, you probably have some form of aggression that your not seeing. When I started my tank, (125) I had fish go missing also, mainly blue hippo tangs. Come to find out, my yellow tang was going after them, in which either stressed them to death or they killed them.

Now that I have my 240, the very first fish I put in, was a blue hippo and haven’t had a problem since. (Well until I added my angel fish, now my clown fish is insane). But, lucky for me, the angel fish is much faster.

It does seem to be a mystery when you don’t find your fish, but as stated prior, they are still in there somewhere. The clean up crew makes extremely short work of them. The only suggestion that I have that may work, (it may not also), but have seen it work before. I would find the fish you want to add, example (blue hippo, purple tang, black tang etc) but instead of adding one at a time, save up and add all three at once. This in theory should lessen the aggression on a single fish. Still very sorry for the losses.

 

[Bob Ander]

Its a huge mystery and I have no clue what’s happening. Every time I add a new fish, it’s gone and there’s no evidence of the body. It’s been happening a lot lately.

I tried adding blue tangs 3 times and they all disappeared. I had a line wrasse and a white clownfish and 3 diamond gobies that all disappeared. I checked behind all the rocks and there’s no sign.

My current fish are a yellow tang, sailfin tang, foxface fish, a few percula clowns, fire fish, and spotted sweet lips.

As far as I see (I check on the tank a lot) I don’t see any aggression at all. No chasing or attacking either. The oldest fish in the tank is the yellow tang. I’ve had it for almost 10 years already. I was lucky to add the sailfin tang, because every other tang that I’ve added has disappeared.

Have you noticed a nitrate spike? That is a sure sign of a decomposing fish.

 

[Miami Reef]

I have a little over 200 gallons. It is pretty big, so they could be missing in there, but I have seen dead fish behind the rocks before. Not all fish go missing, but most of the fish that die are not seen anywhere.

I have fish, corals, live rock, and nassarius/astria snails.

I recently checked my water at lfs and the results came as nitrates very low, but phosphates were at 2. I added a skimmer last week, and I started dosing with liquid phosphate remover.

 

[Bob Ander]

I noticed you said you have clowns. Do you have any anemones? I have had evena medium sized fish get eaten by one of those. Especially if it’s a carpet anemone.

 

[Miami Reef]

I have 3 anemones, but I believe they didn’t eat the fish. These anemones are small and not even clownfish go inside of them.

 

[don_chuwish]

No chance of unknown critters in your rock? Did you start with live wet rock or dead dry rock? Any other additions that could have brought in a hidden night time predator/scavenger? Are the new fish additions fully QT'd before adding? A social acclimation box might be a good idea too - tank mates can get used to them and you can rule out other factors.

 

[Titanwerx]

Look behind the tank or in the overflow, that’s where mine usually end up if they jumped. That’s why I have a mesh cover now

 

[vic5hands]

Did you check back at your local fish store to see if they came back
Chances are they someone else’s food

 

[drblakjak55]

Had a six inch tassel file fish. Went away ten days. On return he was gone. All I found were a couple of spinous processes. Cleaned. Every small Benny, and four attempts with grammas, just disappeared.
Will be using acclimation tank from now on and a mirror. Can a serpent star sneak up and kill small fish?

 

[don_chuwish]

Can a serpent star sneak up and kill small fish?

I've seen it mentioned in many different forums that they can.

 

[bkreitler]

I’m having the same issue. I have a 310 gallon tank. I’ve added fish in batches and didn’t have any issues at first. The tank is about 18 months old now. Parameters are in check. Corals are doing fine. But in the past 3 months, I lost 2 established neon gobies, most all of my snails, a wrasse, couple blennies that were fine for over a year, a few other small fish and now in the past few days a mimic yellow peel tang. Never find the bodies. I check with a flashlight all over and nothing. I wondered if it was my arrow crab or the large green serpent star or the emerald crabs (some are getting large). I am really at a loss. The overhead has a lid, I have a canopy top…. Very perplexing.

 

[vetteguy53081]

I’m having the same issue. I have a 310 gallon tank. I’ve added fish in batches and didn’t have any issues at first. The tank is about 18 months old now. Parameters are in check. Corals are doing fine. But in the past 3 months, I lost 2 established neon gobies, most all of my snails, a wrasse, couple blennies that were fine for over a year, a few other small fish and now in the past few days a mimic yellow peel tang. Never find the bodies. I check with a flashlight all over and nothing. I wondered if it was my arrow crab or the large green serpent star or the emerald crabs (some are getting large). I am really at a loss. The overhead has a lid, I have a canopy top…. Very perplexing.

Emeralds, maybe, others not likely.
You dont have a lg worm in your tank by chance and not know because they hunt at night?
Other would be a Mantis shrimp buy you'd hear clicking.
Another would be stray voltage ?

 

[Spare time]

Could be some disease that you are not noticing.

 

[Miami Reef]

Wow. This was an old thread when I was just starting in the hobby.

Looking back, I think it was disease that was just killing the new fish. I never quarantined back in 2018 and new fish rarely survived while older, established fish were fine. I’m thinking the established fish were immune. Or maybe the new fish were just purchased sick. Who knows.

 

[Spare time]

Wow. This was an old thread when I was just starting in the hobby.

Looking back, I think it was disease that was just killing the new fish. I never quarantined back in 2018 and new fish rarely survived while older, established fish were fine. I’m thinking the established fish were immune. Or maybe the new fish were just purchased sick. Who knows.

Hahaha I just realized the date of the post

 

[Miami Reef]

Hahaha I just realized the date of the post

4 years ago! I remember the exact day I posted this question. I was so annoyed at the person who said I had a monster in my rock! ;Hilarious

 

[JPM San Diego]

How large is the spotted sweetlips? Unless you're seeing aggression, very unlikely that small fish are being harassed to death. That takes time. Likewise, disease takes time too.
Sudden disappearance is much more likely they are getting eaten. If you have something lurking, think bobbit worm or mantis shrimp. Otherwise, if the sweetlips is large enough, they may be disappearing in one large gulp.