hi every body.
I have some 20 inch koi in 2 new concrete ponds . 5 days ago i changed half of the water of the first pond , because of high level of ammonia and PH . last day i lost 2 koi from fist pond and today i lose 2 koi again ( 4 pics above ) . and all kois of first pond now are sick . they have white spot on gill and bloody spot on their body ( 3 pics below ) . the fishes of second pond are healthy . i moved my kois from pond to a big aquarium with new water and still they are not good . please help me that what i do . i love my kois .
please Help me.