Bluestripes are small pipes -- like 3" maximum. And as Diane mentioned, males will fight to the death. You can tell the males from the females in that the males have bumps on their snouts that are easy to see with the naked eye, where as the females' bumps are much much less apparent, often only seen when a clear photograph is enlarged. They are great little pipes, which, when they feel comfortable, will swim all around the tank investigating your live rock.
Dragonface pipes sort of hover over the substrate rather than swim. They aren't a great match with stinging corals because of this. They grow much longer than the bluestripes, but have smaller snouts than, say, the bandded flagfin pipes. I have tried two. The first I lost straight away and I believe the pipe was likely doomed from the start. The second appeared to be much more robust and health than the first, and I though for sure that the pipe and I would be successful. But within a few weeks I lost that one as well, despite the fact that it was beginning to take frozen foods. I'm not sure what exactly happened, as it showed no signs of illness. But getting a healthy pipe in the first place is definately one of the keys.
I owned a pair of banddeds before, and they were lovely pipes. I did have a problem with a coral beauty that wanted to nip their tails, though. Their snouts are a bit larger than the dragonfaces, and, for me, they went onto frozen foods a lot faster than the dragon. They also swim about in the tank, rather than only sticking close to the rock work.
By the way, my bluestripe, I didn't have any trouble converting to frozen. Don't know if I was just lucky with that one or what.
