I'm afraid I made a mistake that killed my rainbowfish. I did a 50% water change and filled my tank with cold water (as I always do). Since this week I had 6 pseudomogil Furcatus in my tank. After the wc five of them died almost instantly. I never had this with my Otocinclus, but maybe the rainbowfish are more sensitive. The normal temperature of my tank is around 25 C.
Is it possible that a sudden drop in temperature killed my fish?
Is it possible that a sudden drop in temperature killed my fish?