Fish dying randomly

[Aliasger789]

Hi everyone!
I needed your help. I have been keeping and maintaining my tank which is 4000 Gallon since last 4 years and the fish have been doing well.

2 weeks back i have got a beautiful live rock near the shore which i placed it in the tank. Since then my fish have been showing spots on the body, poped eye and dying.

I have 2 x4000 G marine tank fish only. i had put the live rocks in other tank as well but all the fish are doing great in that tank not a single mortality there but this other tank i am losing fish on a daily basis , 1, 2 ,3 sometimes even 4 or 5.

My Parameters are

pH- 8.1
KH- 13
Calcium- 450
Mag- 1450ppm
Salinity - 1.023
Nitrates - 25
nitrites - 0
Ammonia- 0
Phosphates- 0.02 ppm

I don't how to stop this. Please help

 

[Dmorty217]

I would suspect possible ich or velvet from the rock or you could be dealing with flukes. If its one of the first two you will need a bunch of copper or Chloroquine phosphate, and if its flukes the same is true for Praziquantel. Another option that will treat all three would be hypo for 30 days straight. You will have to decide which is most cost effective for you being the size of the tank. Something that can help with popeye is epsom salt

 

[ThRoewer]

Since this rock came straight from the ocean it can pretty much be everything.
The way the fish die points to something aggressive like Amyloodinium (Velvet).
You mention white spots on the fish. Are those coming and going in waves every few days or do they stay once there?
Also, how do the fish behave and how is their breathing?

For a whole number of reasons, it isn't a good idea to put a rock you just took from the ocean into an established tank. It is better to isolate the rocks for a while (2 or better 3 months) in a fishless tank or any other suitable container. If you want to keep everything on the rocks alive you will need light and flow and perform regular water changes but don't use water from the ocean for that.