Black Waterfall Foam 12 oz can with dispensing straw. Triple-expanding black waterfall foam. Fish-safe. UV-protected. Use to attach rocks to spillways and to direct water over the falls. Foam works wonders for directing water flow on waterfalls and streams. Easier and longer lasting than normal landscape foam. Regular spray foam is not advisable to use in direct water or sunlight exposure. Keep nail polish remover on hand to remove foam from your hands.