The guy at my LFS told me that colored gravel and colored plants aren't safe for aquariums. He said that bottom dwellers on the colored gravel will start to lose their limbs (ie African dwarf frog) and the cories' barbells will get shorter because they're being burned off on the colored gravel. He said that colored plants release chemicals from the coloring that can harm fish, too. Any truth to this? I googled and found zero evidence of this so I wanted to ask those who may have had experiences. Thanks!