they are very skiddish untill they get used to there enviroment. i had had mine for a while and about for months ago i added a couple tangs to the tank, my firefish hid for 3 months!! just about a month ago he began to stay out all day again
skittish at first but now swims out in the open all the time. be careful when trying to keep more than one, i heard 3 is better than 2 but everytime i tried 3 two always jumped out and left with one.
Its better to either keep 1 or 3 or more, 2 is usually not a good idea. And yes, as a precaution the top of your tank should be secured because they can jump out :nope: