How to Tell if a Dragon Fruit Is Ripe. Dragon fruit, or pitaya, are cactus fruit that come in three types. They can have either red or yellow jp6.infog: jello. Your Produce Guy received some Dragon Fruit in the mail. I don't know how I found myself on this Missing: jello. I tell you how to know when a white dragon fruit is ripe and how to open it without a knife! Would you like a Missing: jello.