I lost another fish today, a bloodfin. That makes 4 fish in the same amount of months. 2 bloodfins and 2 skunk cories. I test my water bi-weekly, everything is perfect, 0/0/5. I sometimes have to add nitrates for the plants. I have, as of currently, 4 bloodfins, 4 cories (2 skunk, 2 green). 5...