I added 3 plants to my pond and two days later the water had a layer of scum and all my fish died. Why?

Question

My pond is 12 ft x 6 ft - the depth is 2ft in the center. Yes it is in the sun.

Answer 1

maybe the plants had some kind of bacteria growing on them.it is hard to notice something like that.you have to be careful what you add to your pond water.you should go to a nursery for there advice before adding anything else to your pond.

Answer 2

Well from experience i don't think it was the plants.  Yes the scum is caused by the sunlight but it is good to have some algae with the fish that is what creates there environment.  Sounds like to me that you do not have enough aeration in the pond on sunny days you need a fountain or some type of water flow to create more air for the fish.  So my best guess is it could be lack of oxygen in the pond.  But the plants did not cause it.  hope this helps

Answer 3

you didn't mention what type of plants they were... conventional pond plants, or other plants that can survive in the pond.   Had this happen when I added a hibiscus to my pond...went brain dead and did not give it a good rinsing before introducing it to the pond.  It had apparently been treated at the nursery for white flies, which in turn killed the fish...the scum may be just the bacterial by product that can quickly show up after the fish die

Thomas' post made me think of that though plants do aid in cleaning of the water, at night the plants (and algae) remove oxygen from the water..not sure what the chance that the plants you added actually tipped the scales against the fish,... but maybe worth researching