| I agree with S teve. It probably was not the orchids... but maybe. The fertilizers used on orchids might have resulted in an ammonia spike if they had been recently fertilized, but so little fertilizer would be involved that it is difficult to believe it would result in a sudden fish kill of such proportions. Sometimes orchids will be treated with copper-based fungicides, which would be very harmful. But, again, not likely enough residue to wash into the pond to cause sudden deaths... and every fish would be affected. If there were other negative factors at work, then I guess leaching from the orchids might have caused some fish to 'cross the line', but I think you would have noticed some issues previously. Something more was going on.
Nonetheless, you raise an excellent point. Care should be exercised with plantings near a pond. I keep numerous potted and hanging plants around my pond, but none over it. The edge slopes away from the pond so water draining from pots flows into the garden, not the pond. When I spray fertilizers on the hanging plants, I either take the plant elsewhere for the spraying, or I take care that the spray is gentle & focused on the plant so no spray drifts into the pond. (A mist of fertilizer would not kill the fish, but who needs more nitrogen added to a pond?... a keeper of waterlillies, but I don't keep plants in the koi pond.) I never use any insecticide or fungicide any where close to the pond, and certainly never anything containing copper, iron or other metals. |