Pond fish is dying
Dear all , I have 15000 lit open air pond. Supported by filtration unit. Pond is operational from last three months. I have 40 small Koil, 8 big Koi, 10 Small moli & 4 Ambamino sharks big.
from last 8 days my fish start dying. every day one or two fish are dying. Climate at my area has started changing. now its days are hot ( 25 - 28 C) nights are cold ( 15 - 18 C).
I have started cooper sulphate doesing & have changes 75% water over last five days.
from last two days not a single fish is eating anything.
Please advice me on this.