FISHIOLOGY

I'm back again to Bichirs but this time more on the experiment that I didn't do last time. When I was once active in bichirs I noticed that some but very very minority of them swim with control buoyancy meaning they can control the depth level like those of ordinary fish using the swim bladder. But in reality; bichirs do not have a swim bladder that is why most time they swim like a drowning fish.  I noticed this behaviour on some Endlicheris, the control buoyancy and of coz the great Turkana Polypterus Bichir Bichir. So my question is, can bichir learn to control buoyancy with their lungs replacing them as the swim bladder?  I got 7 cb Polypterus Lapradei and kept them in a species only tank. Food will be available only as floating pellet. The reason is to encourage them to swim and learn to adapt using their lungs as swim bladder. Will they able to do so? Day 1 of coz they dont eat, I've to start coaxing them to take sinking pellet. Day 2 they are all