Are you asking if the firefish might jump out of your open top aquarium? If so, there's a chance, but I had one for about 6 months with no suicide jumps and then one day it disappeared on me and I never saw it again, so I don't know if it jumped to its death or it just died of unknown reasons.
ive had a purple firefish in my tank since before the upgrade , never needed a cover hes been real cool and if he senses danger he has a hole in a piece of rock he goes into