Mystery Fish Mass Die-Off, Looking for Some Advice

cody6766

Super Best Friends!
Premium Member
I think not QT'ing my fish finally bit me after 10 years in the hobby. Within a couple of days I lost my anthias, kole tang, clown fish and coral beauty angel. Today I found my nassarius snails doing what they do best, cleaning up my dead chromis. I have a lone YWG in the tank now, and wouldn't be surprised if he croaked in a couple of days. All of this happened within a week and there were no signs of illness until the fish died.

Based on the sources of the fish, I suspect the kole tang to be the source of the illness. He was a Pet Co fish and the rest of the fish came from LFSs that QT their fish before selling them. Lesson learned...QT, especially when coming from a less than awesome source.

It sucks to lose a tank full of fish, but so goes life in the reef hobby. The last thing I want to do is toss more fish into a diseased tank. Assuming the YWG dies, how long should I let the tank sit before adding more fish? I'm sure there's a point where whatever killed the fish will eventually die off, but I don't know how long to wait. I also have no clue what killed them and I know that makes advice harder to give. I can tell you that it wasn't ick and there were no external sores/spots. The fish were very active until they died. I did notice that the male clownfish was swimming erratically right before he died. It was a rapid onset and he died shortly after. All others died over night.

So, based on what we know COULD be out there, how long should I wait for it to run its course?
 
I can tell you that it wasn't ick and there were no external sores/spots. The fish were very active until they died.

This sounds more like a poisoning/pollution issue. What do you feed? Any recent cleaning/pesticide events at home? How long did this event take? How long after you added the tang did it begin?

Kevin
 
Hard to say. The lack of observable external symptoms would seem to eliminate ich, velvet, brook or uronema. Bacterial infections usually just hit weakened fish (since the bacteria are always present). Even vibrio/marine tuberculosis will have ulceration symptoms. Worms don’t kill that fast. Some kind of poisinning seems as good a theory as any. I’d run carbon, maybe a poly filter, and give it a month and then try an inexpensive, hardy fish.
 
I feed frozen cubes, the same stuff I've been using for many months in this tank. We haven't sprayed the house in a couple of months and nobody uses cleaning products near the tank.

The whole process has been going on for a week or a week and a half. It started about a week or two after adding the tang. The clowns were the most recent addition and they took around a week to die. The anthias was the first to go, followed by the tang and angel, one clown, then the other, and finally the chromis. I don't think the clowns brought anything in. They were tank raised, from a reputable source and kept in the store's frag tank in a large group.>


Edit: I just realized that the timeline makes it look like I added the clowns while everything was starting to die. I added them a few days before the first fish died and they took around a week to die after being added, plus or minus a couple of days.
 
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That's my assumption. 10 years of not QT'ing fish and it finally bit me. I can't be too mad considering all the success. I mean, it sucks that animals died, but at least my tank isn't big enough to be full of hundreds of dollars of awesome that march one by one down the toilet.

I'll probably set up a QT tank, or at least stick to the places I know QT their fish when they get them from their suppliers. I think that is what kept me safe this whole time. Luckily, OK has a bunch of good LFSs run by honest folks who try their best to sell safe critters.
 
Might it be stray electric causing the mass die off ? 10 years in the hobby , something might have give ?
 
Did you notice any fish hanging out in front of a powerhead? When you get fish from a wholesaler or LFS they often have low levels of copper in the system which only masks symptoms of disease unfortunately and lots of places do this. With as quickly and the mass die off it was either bacterial which you would of noticed on your fish or it was velvet which by the time you see symptoms/spots it’s usually too late
 
I did notice the chromis hanging out with in the powerhead a day before he died. After reading up on velvet, it looks like this may be the culprit. That's good an bad news, honestly. Right now the goby is hanging on and therefore would be a carrier. Getting him out would take a tank tear down, so I'm going to have to wait for him to die or until I can catch him and let the tank lay fallow.

I never noticed any spots on the fish, but they could have been barely recognizable or not showing externally in any substantial amount.
 
Velvet is harder to spot than ich due to how quickly it kills and if you see spots its 99% of the time too late to save the fish. Usually its behavior that will change that indicates velvet not the spots. The goby is immune but a carrier like you said and will need to be treated before being reintroduced to the DT
 
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