From time to time, a guest may wander into the reef, usually when certain levels are reached. The order in which they appear is random for each reef. To keep them, certain plants or other items must be added to the reef. The requirements are different for each guest. Once retained, a guest will not leave the reef, even if the items needed to retain them are removed. Guest information can be viewed on the Guests tab of the Collections option accessible from the menu button. Click on an image below to see more information for that guest, including the requirements to get it to stay in the reef. Each hint is hidden until clicked to reveal it, so you can try to guess for yourself, or find out exactly what is needed!