Fish death

[Big Tank 95]

Did you notice items in your house that needed to be reset? That would indicate the power was off. I would research velvet and if that doesn't fit suspect a toxin of some sort.

No the power never went out + I have back up if it ever does also notice something 2day I have algae growing in the tank a very light flm growing over the rocks and on the powerheads and some spots on sand second time in past 4mo redish color not sure if it's cyano Lights come on at 1:30pm -9:30pm lights start at 30% up 2 80% by 6pm then back down to 50 by 9:30p + 35gal W/C every Saturday at 1:30 pm I dose alkalinity 2 times 15ml at 530 am and 12 ml a 5:30 pm and th same for calcium I use reef fusion part 1 and 2 also test water before W/C

 

[Big Tank 95]

Was the power out over night?
Only the large fish died, corals and the chromis are all fine without any problem. It has to be lack of O2 due to power outage for several hours. We can rule out disease, toxin (or contamination). The only think I can think of that can kill the fish, but the one that live quickly recovered with no apparent effect is lack of Oxygen.

Can you rule out power outage over night?

No the power never went out + I have back up if it ever does also notice something 2day I have algae growing in the tank a very light flm growing over the rocks and on the powerheads and some spots on sand second time in past 4mo redish color not sure if it's cyano Lights come on at 1:30pm -9:30pm lights start at 30% up 2 80% by 6pm then back down to 50% by 9:30 pm + 35gal W/C every Saturday at 1:30 pm I dose alkalinity 2 times 15ml at 530 am and 12 ml a 5:30 pm and the same for calcium I use reef fusion part 1 and 2 also test water before W/C

 

[Tamberav]

It’s sound like oxygen issue to me for sure since all the big fish died overnight simultaneously.

Ammonia in a 15 month old tank where corals and inverts look fine = not an accurate ammonia reading imo.

 

[Big Tank 95]

It’s sound like oxygen issue to me for sure since all the big fish died overnight simultaneously.

Ammonia in a 15 month old tank where corals and inverts look fine = not an accurate ammonia reading imo.

I'll take that into consideration but I have 2 very strong powerheads with good agitation at top of tank wondering what could be done to count that out

 

[keepingfishwithnoidea]

could be internal parsite, operation time!! you still have the fish in the freezer?? i usually do that during mass deaths.

 

[Big Tank 95]

I Didn't save them