Do elegance corals fight with each other?

[asylumdown]

I got a teeny tiny elegance coral for my now defunct 5 gallon pico waaaaaay back in October of last year. It's since been transferred to my big tank, and after an unpleasant early bleaching due to over-doing it with my lights, it's nearly tripled in size and has been one of the happiest guys in my tank.

However, it's not the prettiest of the elegance corals (I bought it because it was the smallest one I could find, not based on colour), so a couple of weeks ago I bought a second elegance that's a little bigger, but MUCH prettier. It's a deep, almost electric green with the bluest tips on the tentacles I've ever seen on an elegance.

They've got slightly different growth forms, and the new one has shorter tentacles, so I'm guessing they're probably not the same species, but since adding the new elegance, my original one appears to be declining. It no longer inflates to it's full size, and has spent most of the last few days practically shrivelled. Even when the body does inflate, it keeps its tentacles small and close to the body, whereas before it let them go long and flowing in the current.

The only thing I can think is that it and the new elegance are chemically fighting, are they known to alelopathically go at it with other members of their genus? I thought that just a problem between different genera of LPS. I don't run carbon, and don't plan to start, so if the general consensus is that they are in fact fighting, I'm going to have an elegance for sale very soon!