hey i used to have a very small brittle star that was a hitchhiker in one of my coral stocks. i kept it and it was doing well for a couple days then disappeared. it was a mini one so it ate detritus and just in case i would give it some phytoplankton time to time bu then it disappeared. suggestions. I'm also not sure if it was healthy from the start because it was a hitchhiker. there is nothing in there but coral so nothing could have eaten it. even open doing a 100% water change when starting to set a whole new structure in my tank i did not find it! it just vanished!