You will want the photo. Do not lift the starfish out of the water to get it. These are Caribbean cushion stars, and they breathe through fine surfaces that only work submerged, so holding one up in the air suffocates it. Guides will tell you a matter of seconds is enough to do lasting damage, and the animal often dies later, well after the boat has gone. This is not a rounding error either. CONANP, the Mexican agency that runs the protected area, has estimated the sea star population at El Cielo fell by close to 20 percent across five years, and it puts that down to people handling them. Touching, lifting, and removing marine life is prohibited inside the marine park, and this is not a decorative rule. Rangers and guides enforce it, people who ignore it can be put off the site, and the park can fine the serious cases. Guides care because their operating permits depend on it. Reef-safe sunscreen is also required by Mexican law at marine park sites, so put on a rash guard instead of another coat of whatever is in your bag, and apply anything you do use well before you get on the boat. Look at them, photograph them underwater, do not pick them up. It costs you nothing and it is the difference between the sandbar still being worth visiting in ten years.