Due to a recent reply to a question I did a search on whether certain plants could be toxic to pond fish. Here are a couple of websites of what should be considered reliable. Is there is an element of truth or is it completely false?
http://www.cnykoi.com/articles/plantpoisonous.asp
http://www.bonniesplants.com/how_to/poisonous_plants_to_fish.html
http://www.cnykoi.com/articles/plantpoisonous.asp
http://www.bonniesplants.com/how_to/poisonous_plants_to_fish.html