What types of invertebrates are easy to keep in a saltwater aquarium?
Invertebrates are more difficult to keep than fish. They are much more sensitive to changes in water quality. If you decide to keep invertebrates, you will have to closely monitor your calcium and alkalinity levels. You will also have to use extremely pure water. Tap water is not an option with invertebrates. For the beginner, hermit crabs, snails, and soft corals are probably the easiest to keep. They are generally more tolerant of water problems.