Is this fish rare?

At a sub-par LFS tonight I saw a fish that I'd never seen before. They were black and white and had a tri-fin tail. It sort of looked like a Penguin Tetra, but had much more unique fins, different tail fin coloring, and was considerably larger (about 3 inches).

Since they were so interesting looking and I had never seen them before, I wanted to see if they are actually rare so I could maybe save them and give them a better home or at least put them in the care of a respectable LFS. I hate to not be able to save all the fish in the cramped tanks (one of the probably 10-15 gallon tanks was full of feeder guppies with about 5 various dwarf puffers and about 3 or 4 silver arowanas - sad), but I've gotta start somewhere.

Okay, so I drew a picture of the fish in Paintbrush with a very uncooperative optical mouse. So, comments on the poor rendering aside, can anyone shed any light on what kind of fish this might be?

Yeah, pretty impressive, eh? I figured this sight needs more contributing artists.

UPDATE: I may be incorrect about the bottom half being black and the top half white with the black dorsal fin. It could be the other way around, but the dorsal is most definitely black. I'm pretty sure it's the way my master rendering portrays.

Some more distinct features I forgot to mention: the pectoral and pelvic fins were both on the bottom of the fish as the drawing shows.

The anal fin runs from the tail to the middle of the fish, much like a Red Serpae Tetra, and was clear-ish with white on the edge.

Also, one of these fish was already dead, so I hope someone can ID it for me.

An idea: it's most likely a tetra, however maybe some sort of Gouramie, but it did not have the "feelers", just the pectoral fins on the bottom of the torso. The salesperson said it was a Blue Paradise He had no idea and was actually digging through paperwork for me to try to find the name. The tank was NOT labeled.

Yup! That's it! I'm just not sure which kind of Emperor it is now, but thanks Aqualung!!!