My plants seemed to be doing well when all of a sudden all of my new growth was becoming yellow and shriveled. The older leaves are now becoming very puffy looking and developing a yellow tinge around the outside edges of the leaves. Have my plants developing some sort of deficiency or is this just normal growth? I have been feeding them half strength fish emultion once a week. Before I do anything and add to a problem, I figured I would ask before trying to correct anything.