Hey,
I am new to this website and I need some help!
I have had a tropical fish tank for ~ 6 years and all of a sudden my fish have been dying like it is going out of fashion! The tank is ~ 50 l and housed 10 neons, 3 glowlight tetras, 2 zebra danios, 2 swordtails, 1 pleo, 1 black red tailed...