There are many different genus and species of fan worms. All of which are filter feeders. They can be kept in our captive environments for long periods of time, but close attention to their diet is needed. They have extremely tiny mouths that can only eat things that are slightly larger than phytoplankton. Usually, these larger particles aren't available to aquarists, so feeding your tank phytoplankton is usually the only thing to feed fan worms. Like all invetebrates, special attention to water quality is needed. Many can tolerate a fair amount of nitrates, but one shouldn't press their luck. Aim for a clean, low to no nitrate tank, feed phytoplankton, and don't introduce future fan worm predators into the tank, and you should do fine.
