[sarahjo]

We have had our 55 gal mixed reef aquarium up and running for almost 3 year's. We have had our ups and downs for sure. But are experiencing an all time low. We have lost a total of 4 fish all within the last 3 weeks. 3 of them in the last week and a half. Not much has changed in our tank. Our parameters are as follows:
Temp: 78
Salinity: 1.026
Ammonia: 0 ppm
Nitrates: 0 ppm
Alkalinity: 11
Nitratites: 0 ppm
Calcium: 550
Phosphates: 0
pH: 8.2
The only thing is we had an awful algae bloom the last couple months and I treated 3 weeks ago with Red Slime and that took care of our algae problem. All of our inverts and coral are doing just fine. Any ideas as to why our fish are dying?? No signs of illness or disease before dying. I'm at a loss! HELP!!

 

[Pitter98]

The red slime / cyano removers can take a lot of oxygen out of the water. Did you leave your skimmer running or add an airstone to your tank?

Did you do a water change after treatment was done and add some carbon to the tank?

Any new additions to the tank lately - fish or corals?

 

[sarahjo]

We left the protein skimmer running, did our normal 5 gal weekly water change after treatment as well. Also changed our carbon about a week after treatment. Added a flasher wrasse about 4 weeks ago, and he is one of the fish that died. But he was healthy and eating, no signs of illness when we bought him or during the month that we had him. Other than that nothing else was added to our tank.

 

[Pitter98]

Sounds like your regimen for the slime remover was good, so that shouldn't have been the problem.

I am going to guess that the flasher wrasse brought in something. If you didn't quarantine (it is always easier said than done), he could have brought in a parasite or disease very easily that spread to your other fish. It is tough to know what it could have been though. Do you have any pictures of the fish as they were declining or post mortem?

Any tattered fins? Cloudy eyes? White spots? White stringy poo? There are a lot of possibilities for stuff that wipe out multiple fish, it is hard to guess without more information. Anything unusual about the fish would help with potentially diagnosing.

 

[weimers75]

I too am thinking an oxygen problem since inverts and corals are fine...but the new addition is also suspect. Look up at the surface of the water from below. Does it seem oily? Hows the flow on the surface?

 

[Dragonhunter103]

Had same thing happened to my tank. Lost 6 fish including my mandarins. Found out something brought Brooks into my tank. I'm in the middle of quarantine for my 4 remaining fish treating with copper aid. Last fish added was an atlantic bue tang. But even invertebrates can carry Brooks.
Brooks can live without a host for up to 8 weeks. Recommend doing a fw dip for remaining fish and quarantine for 8 weeks. If you have a uv sterilizer run it on your main tank for 1 week to help speed things up.

 

[ajmckay]

How is the tank doing now? Any more losses?

So I'm at a loss... The timing doesn't seem to coincide with anything.

Were it an infection or a parasite there would have been some sort of symptoms. Anything from twitching, listlessness, lack of appetite, lethargy, physical changes, etc... It's completely possible that some symptoms were missed though. If you've had the tank for years you probably don't search over the fish looking for issues at this point. So an infection or parasite is an issue.

Since other fish and corals were doing fine I would think it unlikely that it was the red slime remover or an issue with your maintenance routine (like accidentally doing a water change with FW). Same with a toxin or some sort of equipment malfunction.

Anything else you can think of that changed around the same time?