jumping firefish?

[niloc16]

i use to have a purple firefish for a few months and then after i purchased my flame angel he jumped out. i want to get another purple firefish and a red firefish at the same time. i am trying to figure out how often they do jump. i know they are classified as jumpers but from the people i talk to at the LFS say they rarely get them jumping. any advice to lessen the chance of them committing suicide would be great. i currently have pair of black percs (had for a week), flame angel, sixline wrasse and a blue/green chromis. i dont want to cover my tank but i was thinking of maybe using egg crate on top for awhile to get them used to the tank.