Beta fish help please?!!?

i have a male beta fish and he is about two months old.. i have him in a big enough tank with some pebbles at thee bottom and a plant.. i also have a light behind him with a moving picture of fish in an aquarium.. none of them are beta fish and he really loves it. his behavior seems to be normal but at the very tip of his tail fin its starting to loose color.. whats wrong with my little nouget?! :o (thats his name) hah