Not really.
They cannot be kept with small fish - they'll get eaten.
They cannot be kept with nippy fish, like the barbs or gourami - its ventricle fins will be bitten at.
It can't be placed with other topdwelling fish - its territorial and fast fish can freak it out.
It MUST, repeat MUST have a VERY tight fitting lid (duct tape to cover any gaps if necessary). They can and WILL jump. I can't recall who it was but someone here posted pics of their beautiful butterfly and then updated to tell us that it jumped out and died.
They also need a tank of 29g or larger, In my opinion, because they only utilize the surface area of the tank. The rest of the area does them virtually no good so they need a reasonable sized "home" surface area.
They do not tolerate heavy water currents, since as you mention, they float. They also like floating plants and tall plants that reach the surface.
They can be difficult to feed as some will not accept non-live food. Find out what your LFS feeds them if you decide to get one. Unless they will accept flake food/krill/etc, it's best not to get one unless you can stomach feeding live foods such as crickets.
Their scientific name is pantodon buchholzi.If you do a google search you'll find tons of info on them
http://www.aquahobby.com/gallery/gpantodon.html
http://species.fishindex.com/species_2911pantodon_buchholzi_african_butterfly_fish.html
http://aquaticadvice.com/level2/profiles_f/butterfly.html
hope that helps
