In the default camera mode, you are free to control where to go in your reef by swiping with one finger to move, two-fingers to rotate, and pinching in/out and zoom. You can tap on just about any UI menu, so don’t be shy. You can select a creature just by tapping it as its swimming on your screen. If you see parts of the UI disappear, it will hide after some idle time so you can better observe your creatures, just tap the screen and the UI will re-appear.
In the bottom right, your will see some icon buttons. These are useful buttons that help you navigate your reef. From the right, is the Home menu, Creature list, Next and Previous creature, and Camera mode toggle.
You can tap on a creatures swimming by anytime to select it. However, the creature list can be the best way to find one of your creatures or collect hearts quickly by tapping on the H. The Previous and Next buttons are also a very easy way to navigate through selecting your creatures.