*** been playing with this over the years and a number of things seem to play a factor in this with the fish.
1. size of tank and amount of fish in the tank (*** noted small amount of fish in a smaller tank seem to feel unsafe)
2. type of light used in the tank (seems bright unnateral light can cause fish to sittish)
3. amount of food given in one day, fish tend to hide more with a full belly vs when they are hungry they tend to be less sittish ( *** also linked this to agression , the more they are feed the more time they spend chasing, fighting and guarding teritory, rather than looking for food)
*** noticed anyone of these factors can lead to the sittish trends , these are just my own personal observations. Im sure there are other factors that can cause this but these are my top three. hope this helps bro.