Fish all look sickly, yet water seems fine...HELP!

[hfp75]

2 days and a dead fish should be gone if you got a CUC. Sometime I just toss in a silverside for them to munch on....

Mines a 55g Main & 10g sump

[daniella3d]

maybe one fish died and caused ammonia, and that can burn the remaining fish or create a lack of oxygen. 16 fish in 150 gallons is a lot, unless they are all small fish. It's 5 gallons of water per 1'' of fish, so that's 30'' of fish, devided by 16, all your fish would need to be like 1.8'' and I am guessing they are much larger then this....

Just overstocked I guess. I don't know the size of your sump but that still make it a lot of fish. Even in 200 gallons your fish would need to be 2.5'' each.

[newreefer_59]

I think that may explain the sickly looking fish.

[asylumdown]

Well, the first question should be what killed the tang? I'm sure a rotting fish in the water didn't help if it was a decently sized animal, but fish don't just die for no reason. Unless you've had this tank for years and years, chances are good it wasn't old age. If something stressed that guy out mortally there's a good chance others are being subjected to the same pressure.

[newreefer_59]

but we just saw another one today. looks to be around finger width and 5" long, so was not as large as the firsy one, but is still pretty big. Would that have been a cause and should I try to remove it?

[asylumdown]

Wait I'm not sure I understand... how many dead fish are we talking about here? 2 dead tangs in quick succession?

Yes if there's a dead fish in there you should absolutely remove it. Also test your water for ammonia, nitrite and nitrates. You don't want to start a chain reaction and crash your whole tank.

The question is why are your fish dying - how long have you had the ones that died? when was the last time you added a new fish? Are you sure they're getting an appropriate diet? Is there aggression issues in your tank that's preventing some fish from being able to eat or stressing them out badly? Are there any symptoms of disease on your other fish - specifically look for small white spots on your tangs, as they're most likely to show visible symptoms of ich if this is an issue.

If you experience multiple fish deaths close together, there's likely a much bigger problem going on. Either disease, water quality, nutrition or the social structure of your tank is out of whack. What kind of tangs are we talking about here? They're not all created equal, and if you've got something like a sohal in with 3 smaller and more docile tangs in a 150 gallon aquarium it's basically a recipe for carnage.

[naesco]

Originally Posted by asylumdown

Well, the first question should be what killed the tang? I'm sure a rotting fish in the water didn't help if it was a decently sized animal, but fish don't just die for no reason. Unless you've had this tank for years and years, chances are good it wasn't old age. If something stressed that guy out mortally there's a good chance others are being subjected to the same pressure.

What asylumdown said but:

Both a powder blue tang and an A.nigricans (looks like a powder brown tang but has no orange on it) will die for no apparent reason most often taking a few of their tankmates with them.

[Aquattro]

Guys, he's talking about finding a second bristleworm And no, the worm didn't cause anything, they're good to have.

[newreefer_59]

So even though the size of the worm is about 5", he is fine to be left alone?

Ok, so this is what occurred. I had 16 fish. 4 Blue green chromises. several damsels and a percula clown. A Flame angel. A goby. One yellow, Tomini, Sohal and Naso tang that were all about 4" in length. Last night when I arrived back home, I found the Tomini, Naso and Sohal tangs and the Flame Angel all dead and trapped in the live rock and all in the same spot.

It happened Monday as ALL the other fish looked very stressed and sickly. At Wed, they were all looking better, and i found and discarded the dead ones last night. They did not appear attacked though hard to tell, but very decayed. I did another water change, and all 12 remaining fish, crabs and corals look completely fine.

Any thoughts as to what may have happened to the 4 fish that all died in the same spot? under the live rock?