Do you have a photo? It may not be fungus that is growing on your plants, but algae.
I do have a picture. Quick background on it. I've put a couple of threads out to figure out what it is. No one really knows. I was told it was hydra, I treated my tank for 3 days straight with dog dewormer with fenbendazole. It had no effect on it what so ever. I've done experiments in cups with a extremely high dose of dewormer, nothing happens. I also treated it with hydrogen peroxide and excel. With no effect on it. The only thing that kills it, is a bleach dip. But its all over everything so I can't use bleach. I took a sample to petco and talked to the fish guy there, he said it looks like a fungal issue and said I should try prazipro.Do you have a photo? It may not be fungus that is growing on your plants, but algae.