My neons are dead

[DigitalBoy]

Yesterday I've found out that half of my neons is dead, my water quality is good, it is veery strange. Any ideas what could've caused it?

 

[Neil]

What other inhabitants do you have in the tank? How long have you had the neon? And how do the other neons look right now?

 

[aspen]

check all of yuor other neons for ragged fins, esp tail and 'adipose' (the fin in front of the tail, on the top) if it is agression from another fish, they will often fin' them first to slow them down. do you have any fish like drwarfs or other cichlids go into breeding mode lately? if not agression, i would be hard pressed to figure out how an established group would all die so quickly. they are not the hardiest of fish, and i have found they will die one by one, unless there is a serious problem with your water.

rick

 

[DigitalBoy]

Here's what I have

I have a pair of apisto cacatuoides, 3 SAEs (as of yesterday 2, I found the other one dead!!!), no neons in the tank right now - I had 10, but now I have 3 and they are in my quarantine, 2 guppies and 3 corys.
Fish do not show any signs of disease, water quality is good, there are no ripped fins. Neons, however had some itch (only 2 of them), I figured it is caused by stress of some sort.

 

[Charlotte]

Have you added ANY medication or absolutely anything out of the ordinary to the tank during about the 7-10 days prior to when they died? What about your water change schedule?

Any medicine I have ever used to try to treat intestinal parasites has made my neons turn pale in their red color, some got a little ick, and then dropped dead within about 5 days.

 

[DigitalBoy]

No

No, I have not put any medicine in the tank for months, and I also did regular water changes about 30-40% every 2 weeks.