Mysterious Powder Brown Tang Death

[ryanat25]

My Powder Brown Tang passed away this morning. I’ve had it together with a Purple Tang in QT for 3 weeks now for observation and acclimation. Water change every other day. Both Tangs are vigorous eaters. I feed them mostly Nori 2-3 times/day and a sprinkle of New Life Spectrum daily… no left overs. They eat off of my hand. No signs of disease, 0 aggression except their first 2 nights together.

Last night, I was about to dose Copper Power. I put both in a small breeder box while I do a 100% wc and full wipe down of the aquarium. I filled the aquarium back up, dosed with copper… an hour later (without putting the fish in copper yet) I noticed the PBT on its side barely breathing in the breeder box! The Purple Tang is fine. So I emptied out the copper and put them back in regular reef water but the PBT didn’t make it through the night. I’ve heard these fish are sensitive but I’ve never encountered anything like this. Just to add, I initially caught them by cornering and scooping both up using the breeder box without any struggle. Any thoughts?

 

[Spare time]

A common thing that @Jay Hemdal mentioned once is that people let disease get a foothold by slowly ramping up copper (or by doing observations first), then conclude that it was the copper that caused the issue. The fish are not sensitive to copper. My best guess was a parasite was able to infect the fish because it got to the fish before the copper came into play. The only other thing I would think of would be some dip of oxygen that caused an issue. Whether or not the latter is the issue I can't say with certainty, but it is something to consider.

 

[ryanat25]

I was thinking it could be the oxygen also. If it was, I could smack myself in the head for not putting in an air stone… 2 large fish breathing heavy from stress in a small container. Couldn’t be disease because the PBT was swimming normally and even feasted on a thick piece of Nori prior to transfer. Even if it had disease, it couldn’t have died just within the hour because of it. That’s the reason I waited 3 weeks before copper treatment.

 

[Jay Hemdal]

I was thinking it could be the oxygen also. If it was, I could smack myself in the head for not putting in an air stone… 2 large fish breathing heavy from stress in a small container. Couldn’t be disease because the PBT was swimming normally and even feasted on a thick piece of Nori prior to transfer. Even if it had disease, it couldn’t have died just within the hour because of it. That’s the reason I waited 3 weeks before copper treatment.

Sorry to hear. Unless you made an error with the copper dose, it wasn't that. More likely it was oxygen deprivation or stress from being held in the container.

Jay

 

[jda]

I don't know if this is your case, but my largest issue with adding copper to a tank over time with fish in it is that the copper can kill things and the added decaying organics can use up oxygen. Not all fish are as sensitive to low oxygen levels are others, so it is possible that one can die while another is fine.

...or, most of the time fish just die and we will never know why.

 

[ryanat25]

Sorry to hear. Unless you made an error with the copper dose, it wasn't that. More likely it was oxygen deprivation or stress from being held in the container.

Jay

Yeah poor guy. Can’t be copper because I didn’t get the chance to put it in copper yet. You know you think you’ve taken all the precautions already… another hard lesson learned.