How do you keep starfish alive?


I got starfish when I was just starting out. The only one that made it was the serpent star. I still have it. I had to move it to a bigger tank because it just kept growing. That thing’s tough. I don’t know what to do with it to be honest. I still have no idea how to take care of other starfish. I’ve tried a few times but still had no success. If any other reefers have any starfish care tips I would appreciate it. If this post seems familiar it’s because I already posted it as a reply and then realized more people would see it if it was a new topic.