On Oct 3, 10:19 am, avz10 wrote:
I have rebuilt my pond and added a "flower box" under the water fall. I
have tried on numerous occasions to put fish back, one or two at a
time, but they all die.

I have tested the pH, etc of the water, the paint is safe to koi, so I
suspect the plants.

Any ideas what might be the culprit, or other ideas?

Some good advice from Nanzi and John
I also thought perhaps there is something in the Potting mix you are
using.
Is there a fertilizer in it or are you putting a fertilizer/plant food
on the ferns?
Emilie
NorCal