can somebody help me, my parameters are all normal but all the new fish I add to the tank keep dying

[Kayvon]

I'm also thinking velvet. I had a similar incident in my tank. I had pritine water and tons of flow, but the whole tank was dead one day. Did any of the fish exhibit a white fuzz on their bodies when they died?

 

[Jay Hemdal]

are mandarin immune to velvet?
i'm not particularly familiar with marine fish illness, I've always been more involved in the coral and just use fish as movement livestock to give the scape some energy.

Not immune per se, but resistant.
I’d just run the tank with its current stock for 30 days (45 would be better) to let things settle out.

Jay

 

[zeszes]

I'm also thinking velvet. I had a similar incident in my tank. I had pritine water and tons of flow, but the whole tank was dead one day. Did any of the fish exhibit a white fuzz on their bodies when they died?

Can't say they did, the bodies looked pretty normal if. Would velvet also explain how quickly the flasher died too?

 

[ferguccini]

this sounds very like an ammonia spike or something toxic in the water

 

[zeszes]

this sounds very like an ammonia spike or something toxic in the water

It wasn't, I listed my parameters in the first post. I've actually been having problems lately with low nutrients and have actively been trying to get nitrates and phosphates up a little bit. Regarding ammonia. I do regular checks when I add fish without qt just to be sure I don't need to do an emergency water change. I'm pretty sure they're probably right about velvet.