Fish Dying Mysteriously

Baseball#27 · Jan 27, 2021

What's up guys. recently a lot of my fish have been dying and any new ones that I've been putting into the tank have also been dying. Every single fish that has died seemed extremely healthy the day before - eating and swimming around, looking totally normal - and then I just find them dead on the sand the next morning. Everyone is very peaceful in the tank and they get along well. I thought the issue may have been flow and water surface agitation/ not enough dissolved oxygen. I went out bought a vortech mp40 about two days ago and now I have very good surface agitation for better dissolved oxygen rates, however, today I found my yellow tang dead. I will be checking for stray voltage today but everything I have in my tank is fairly new so I doubt that's the issue. But I was wondering if you guys have any insight on this mystery. I'm honestly baffled at why these fish keep on dying. They look perfectly fine the day before and eat well. They show no signs of ich or anything. I've been in the hobby so far for 4 or 5 years and never experienced something like this, I'm genuinely confused. Hopefully some of you might have some insight.

Parameters:
Salinity: 1.025
Temp: 78
PH: 8.3
ALK: 10
Calcium: 450
Mag: 1350
Ammonia: 0
Nitrites:0
Nitrates: 10
Phos: .1

LeftyReefer · Jan 27, 2021

What are the current (surviving) occupants?

Baseball#27 · Jan 27, 2021

Just my Hippo Tang. I also have two cleaner shrimp which are doing fine. However, today he has just been wedged on the side of a rock. I've had him for a year and a half, really healthy and this seems a little weird for him to do in the morning.

Baseball#27 · Jan 27, 2021

So far within a month: My OG Yellow tang died, Got a new one a week ago and that one died today, my two clownfish of 3 years died (got one new one and that one died a week later). I thought the deaths of my original yellow tang and clownfish were due to low oxygen originally but now since both my new yellow tang and new clownfish died with the new vortech mp40, I honestly have no idea what is going on.

StlSalt · Jan 27, 2021

Could something have gotten into the water accidentally? Have you run any carbon? or maybe Chemipure elite? I don't know what all the colors mean I use carbon so somebody else might have to help with the right product there. Maybe an ICP test? Do you have pictures of any of the dead fish?

LiamPM · Jan 27, 2021

What size tank is this and is it an upgrade or new tank? Being in the hobby 4 or 5 years so im assuming its some sort of tank upgrade?

Baseball#27 · Jan 27, 2021

This is a tank upgrade. The tank is about 5 months old and I added all my live rock from my old tank into this one as well as some new live rock. I put in the fish about a month after I filled the tank to be on the safe side. I am thinking about doing an ICP test to figure it out. So far I haven't run carbon or chemipure. I should have took pictures of them but I didn't. When the fish died I looked them over to make sure there was no parasites on them/ any fin rot and I continuously found nothing of that caliber

LeftyReefer · Jan 27, 2021

I'd definitely do an ICP test if all your regular parameters look OK.
In the meantime, I'd start running some carbon and hope you pull out whatever is in there that is killing your fish.

Is your ALK always 10 +/- ? Do you dose this tank?
Have you rechecked your salinity and your measurement tools?

Your ALK, CA, and MG are all relatively high.... maybe your salinity is actually higher than you think?
That might also explain why any new fish die within days.... a lot of LFS run low salinity in their tanks.... perhaps the fish are having trouble adjusting to your salinity if its actually higher than your think, coming from the low salinity LFS tanks... just a thought.

I'd double/triple check your salinity and even have an LFS check it if possible too.

Sorry about your losses.