what type are your 5 and NO they will not last in your 60g tank. smallest:12" - biggest 30+" and they all grow fast at first if power fed but once they get around 9-10" there growing slows down. just tell us type and what size you have now and believe me we will have the stats you ever wanted for your bichirs.
holla back and check my gallery! i have 6 in a 120g.
I have a few senegals. They have been growing very slowly. (About 4-5" in a year.) They eat cichlid pellet food mostly with some frozen bloodworms mixed in. (I used to feed them live black worms, but I got a bad/diseased batch which wiped out my weather loaches. Hence I have stayed away from live foods for now.) One of my guys likes a carnavore pellet I used to feed my baby arowana. So I usually add this into the mix as well.