For new tanks, it may seem like progress is taking forever, but patience at this stage is paramount. Various types of algae will invade your rocks, and your tank will become full of all sorts of critters that you just don’t have a clue as to their identity. Don’t freak out. Just sit on your hands and wait. All new tanks go through this stage, as the nitrifying bacteria are in the process of establishing equilibrium in the nitrogen cycle and the various critters on the rocks will take advantage of their being an abundance of decaying organic matter and no predators to fear. As the tank matures, however, these organisms will give up their dominance to different life forms, such as coralline algae and other more complex creatures.