Marine Invertebrates are a great addition to your saltwater aquarium. Some are great for maintenance to your saltwater aquarium environment. It is always good to verify compatibility of your inhabitants and that includes invertebrates.
Some invertebrates serve as good janitors to your environment. Some eat microalgae, detritus, and pest off of fish and rocks.
Sea anemones can be a good addition to your saltwater aquarium, especially if you have an anemone fish in your aquarium. These fish like to live and play in the anemones, and this interaction between the fish and the anemone is an entertaining sight. Sea anemones attaches themselves to rocks or substrate with a foot called a basal disk. It uses the basal disk to move around the aquarium. Sea anemones have stinging tentacles and need to be watched if you have coral in your aquarium.Sea anemones can split and you might end up with more than one. Sea anemones require excellent water condition and moderate to intense lighting, they have a symbiotic algae living in them. This symbiotic algae (Zooxanthellae) provides them with most of their nutrients, but to keep them healthy you should feed them directly with meaty foods 2 to 3 times per week. They also require moderate to strong water movement.
Tridacna Clams are beautiful mollusks to add to your saltwater aquarium. They attach themselves to rocks or substrate with their muscular foot. Once they have attached themselves try not to move them, because it can damage their foot or other tissue. They have a symbiotic algae living inside them, from which it receives most of its nutrients. Tridacna clams are filter feeders and can be feed phytoplankton 2 to 3 times per week. They require moderate to strong lighting and low to moderate water movement.
Crabs are great scavengers, and they are an excellent addition to your saltwater aquarium. Crabs eat algae and detritus off of rocks and substrate. They are relative easy to keep, and some occupy shells for protection.
Shrimps are one of the most colorful crustacean and a wonderful addition to your saltwater aquarium. They are also scavengers, eating more than just algae and detritus; some eat parasites off your fish and other pests within your tank environment.
Snails are good scavengers to add to your saltwater aquarium environment. Some are herbivorous, eating algae off rocks and glass; others are omnivores, eating meat and algae.
Starfish are known by their five arms extending from their body. They eat detritus and other organic matter within your aquarium. Starfish do an excellent job keeping your live sand bed clean. Use caution when choosing a starfish, because some will eat your coral.
Sea urchins are known by spines that radiate from their round skeleton body, they are also great scavengers eating algae and detritus. Sea urchins have tube feet that they use for locomotion.