Attempts to keep them in home aquariums are best achieved with high rate of success if you have a very large tank with an established marine population. They require sand beds at the bottom of the tank with adequate rocky setup (live rocks) so that they can hide from the attention and for shelter to stay away from the lights. Starfish makes one of the best scavengers apart from your shrimps and they will readily consume mollusks such as mussels or clams dropped into the tank or they can even feed on the coral polyps. That is why having a huge tank that can easily sustain itself is the key to the survival of all these creatures as they can interact both symbiotically or reproduce fast enough to support the overall growth of the marine population. But beware; if your intention is to breed saltwater clams, then I would suggest dropping your plan to keep the starfish as your colorful clams will end up becoming foods. Most of the common sea stars species which are famous within our hobbyist community are the sand sifters, chocolate chips to the more exotic Fromia which includes the Orange Marble types (as depicted in the above picture) including the blue color Linckia laevigata. Sometimes people also made the mistake of grouping the brittle stars into the starfishes group although both of them belong to different classes with the former showing faster mobility and having a more slender thinner body.
Tank Setup Guide
Aquarium setup to keep your pets should have at least a protein skimmer because sometimes slight concentration of toxic content build-up especially ammonia can easily affect their health. Ideally the tank should also be equipped with a pH probe so that you are aware of the changes in the pH level and react fast to contain the situation. Calcium content in your sea water is also another parameter you will need to watch out for as deficiency in the concentration can be harmful to your sea stars. If possible maintain a constant SG so that this will keep the stress level down. Also make it a habit to routinely check for any presence of holes of abnormal patches appearing on their body because it can mean infection caused by fungus or parasites. Nevertheless when adding a new marine starfish, try to ensure that you place close observation whether they can blend in well with the rest of your tank inhabitants because certain wild species are even known to kill fish and destroy reefs. For certain species such as the chocolate chips sometimes you need to place a close watch just to understand their interactions with your other pet fish because puffers and wrasses are known to attack and consume them while even the small-sized cheeky dottybacks can sometimes threaten up to the extent of causing injury.
Breeding and Reproduction
Starfishes if well cared for will reproduce by sexual means with the opposite sex living within the aquarium confinement but however, it is quite rare to actually see it happening. Of course the more famous approach is by fragmentation to cut off part of their arm but make sure that you don’t end up damaging the central disc as this will potentially kill them instead.