Dead fish over night :(

[FishFan4]

I have a chiclid tank that that been up and running for a few years nothing new added and yesterday four of my fish died. I did a large water change and then today 2 more died and the water is milky ...any ideas

[mgarrido]

Check you parameters (ammonia, nitrates and nitrites). A milky water is normally a bacteria bloom but it's rare in old tank (not impossible). How is your maintenance schedule? How big is your tank and what is your filtration? A little more info would help to find the source of the problem.
Btw welcome to HFB and sorry for your lost.

[Dow]

Note, they did a huge water change. My theory is "new tank syndrome."

[jhenry]

Note, they did a huge water change. My theory is "new tank syndrome."

What is the problem with huge water changes? I don't Recomend doing a large WC out of the blue but I do 90% WC everyday for at least two years now. But I will say I do have to work new fish up to that level over a months time
But we do need more info before we can make a informed judgement

[fshfrk]

what is your location?

[TonyO]

Did you clean the filter (change out media) along with the water change?

Definitely check the parameters, especially with the cloudiness. Check your tap, as well, for a comparison.

I, too, will do large scale water changes periodically (normally, I do the 20-30% at a time), but I have heard stories of this happening from time to time.

[sountfc]

I read this differently: He said four died, so I think he then did the large water change. It doesn't sound like the water change was responsible for the initial deaths. With that being said, I agree with Justin, I do large (75%) water changes all the time, no issues. Something doesn't make sense.