Help with new fish dying

[HWDylan]

Hi, I have a 75gal mixed reef tank that has been up and running for about a year now. My 3 fish (black clown, YWG, and 1 chromis) inhabitants are all healthy and happy and have been that way for quite a while (~6mo). I have recently decided that I would like to add a few fish to the tank so I got a Foxface. I acclimated him properly (dripped for ~1.5hrs) and put him in. He was fine for a few days (eating and everything) and then last night he looked pale and was breathing very fast and now he is dead. I would write this off as a fluke if this wasnt the 2nd foxface to do this as well as a royal gramma and a Kole tang. All were dead within 2 weeks of being in my tank.

What could the issue be here? I have tested as much stuff as I can and everything looks good.

NH4: 0ppm
NO3: ~5ppm
PO4: ~0.01
Ca: 470
Alk: 9.1dkh
Mg: 1350
Salinity: 1.025
Temp: 79.8 - 80.0


What could be stressing these fish to the point of death so quickly in my tank? The other inhabitants of the tank basically ignore the newbies so it isnt them I dont think.

 

[Marshall O]

The only thing that comes to mind is that 1.5 hours is actually a long time to drip. I would recommend floating the bag for 15 minutes to get the water up to temp, then drip for ~30 minutes to get the salinity and pH to match. If you do too long of a drip, it is possible the water temp can drop in the acclimation box/bucket much below the DT temp. That is about all I can think of though. I would recommend QT'ing all fish first though in a separate tank.

 

[Deinonych]

I would recommend QT'ing all fish first though in a separate tank.

+1

Using a QT allows you to match the salinity of the tank to that of the LFS. That way, you don't have to drip-acclimate. Just float the bag to match the temp, add a little bit of tank water two or three times, and plop them in. You can then raise the salinity of the tank slowly over multiple days. I've never lost a fish using this method.

 

[shaka]

Quarantining new arrivals is always the best thing to do. But I'm wondering if the source of the fish might be an issue as well. Where did you buy them ( LFS or online)? If they are reputable they should be able to help you figure out why the fish died. Also, could the fish not have been in the healthiest shape when you purchased them? Were they eating at the store? Could they have shown any signs of disease or have an emaciated look about them?

I realize you probably chose the best looking fish to buy, but sometimes we overlook "things" when we are caught up in the moment of buying. I once saw a customer buy a Copperband butterfly from a LFS even though it was very emaciated ( sunken area behind the head ) and without seeing it eat. He just took the salesman at his "word" that the fish had been eating.