Hi guys,
I cleaned my tank today - approx 60% water change and did all the usual things and I looked again after about 4 hours and around 80% of my fish have died, including my 6yo shark . I was just wondering what could have caused this? I did what I usually do when I clean my tank, it has been set up for about 4 months now with no deaths, all my old fish from my older tank, my shark, my danios, my loaches and catfish have died, but my two gouramis have survived...
Quite distressing.
Help?