Are the poisonous?

[easplund]

I put a new mushroom polyp in my aquarium, but is disappeared almost immediately. All I saw was my angelfish lurking in the area where I dropped it in. The next day, the angelfish won't eat anything, and he just sulks behind the rocks. Normally, he is an absolute pig. Are these mushroom polyps poisonous to fish, such that they could cause his strange loss of appetite if he ate one?