Im not too worried about jumping. I have a tight fitting glass hood, and i have sponges in the area between the backplate and the fittings.
Sort of on the same topic. Why do firefish flick yheir fins out every so often?
I think there would be a prob. too, the purple firefish is actually a semi aggressive fish, while the normal red/white firefish is very peaceful, and since they look almost identical, im pretty sure the purple will pick on the other.
I saw these exact 2 fish in a system at the LFS the other day. I think it was in a 35? It was one of those ones with the filter and light and everything built into the canopy. Anyway to my surprise(i thought the were aggressive toward each other) they got along fine and even swam together. I asked the guy at the desk if he had any problems, and he said "NO. Firefish like to be kept in groups" I said "Really? I thought the were agressive toward each other and fish that looked like them?." He said "Nope. see i have 10 of them in the same tank."(a different tank.) Maybe he was lucky, but i think its worth a try.
If your ever in windsro check out discount pet. You will see the 2 fish in the aquarium.