Came home to find 7 dead fish!

[rhite]

I came home this evening and found 7 of my fish in the community tank dead. The worst was my Gold Nugget Pleco. I have no idea what went wrong between yesterday and today. The tank is a 30g and has been running great for months. I found a few white spots on one the cherry barbs so I did a 50% water exchange and dosed for ick. Before the water exchange: Am = .25, PH = 6.8, KH = 120, GH = 25, NO2 = 0, NO3 = 20. PH may have been a little low but I have no idea what went wrong.

Death Toll: 4 Cherry Barbs, 2 Green Tiger Barbs, Gold Nugget Pleco

Survivors: 3 Tiger Barbs, 2 Cory cats and an Apple Snail

 

[BayArea_510]

ich treatment to powerfull

 

[rhite]

What would you have suggested

 

[nfored]

Why do you have any ammonia in a tank thats been running for months? granted its low and the low ph helps keep it less toxic but still its ammonia. Hows the surface agitation could it have been O2 depletion I killed my beloved RTBS like that when I changed the angle of the output from the filter.

 

[Mikemonteiro]

i dont think i wouldve done a 50% water change in a 30 gallon before putting medication you could've added more beneficial bacteria they sell bottles like that at pet shops i mean maybe that could've helped a little. if you dont like using chemicals haha.