i have a 40g tank.. there are tiger barbs,corys,guppy,mollies, & danios..
my tank is cycled and had all my fish for more than 1 month now,
problem is that, why is my corrys started to die 1 by 1 every 2 or 3 days?
i change 50% of my water every week or 3 days
water has no chlorine since i got...