Nutrient fish die off?

[surfingwel]

I have no idea how this happened but i had few fish die one after another

My skimmer stopped performing for a day or two.. i tried to tune it to best I can before a replacement showed up

I've tested the water and I saw an ammonia spike to .09

Long story short few fishes passed,
I've done 10% water change dosed seachem prime etc but next morning two more did not make it

Strangely enough all of them were new fish I got online ones this week and few several weeks ago which they have been doing quite well to this point

but ones I've had for a while seem to have powered through it

I did another big water change today since my salt also arrived just in time and things seem stable now

How is it that just newish fish got totally wiped out

 

[lapin]

My guess is;
they were diseased when you got them ; your tank has a disease that your long time fish have been able to fight off.;
One of your older fish killed them.
Not much to go on.

 

[surfingwel]

I was thinking a disease too.

I saw two fishes gasp for air and flip around. One angelfish which I know are sensitive woke up to it being upside down :(

 

[Mr. Mojo Rising]

Its hard to say without having more information, but sounds like you've been adding batches of fish within a few weeks apart. Again I don't know but depending on tank size and tank maturity it might have overloaded the system.

 

[The Ugly Phase]

I was thinking a disease too.

I saw two fishes gasp for air and flip around. One angelfish which I know are sensitive woke up to it being upside down :(

maybe oxygen?

 

[Jungle Blue]

maybe oxygen?

I second this. Encountered something similar when I batched too close in the beginning (coupled by dosing bacteria in the evening; more O2 consumption). I think my O2 tanked and it stressed the fish out bringing out dormant illness, dominoes.

By routing outside air into my sump, not only did it correct my O2 levels, but also keeping my Ph above 8.0 without additives (was struggling with corals/macros too). Current fish are good, and new additions settle in within 2-3 days. Giving 2-3 weeks in between batches now.