Oh no! I ... uh ... I don't name my fish at all then. Yeah, that's my story and I'm sticking with it.
ops:
Actually there are only two fish I refer to by name (oops I mean my "wife" refers to two by name). One is Half-Pint-O-Tang, who was named by ... um ... our own EmilyB (the "Em"issary?
) and Rygel, the lawnmower blenny. Fans of the show Farscape will understand the name.
Farscape is a really off the wall show. Put out by Jim Henson Studios. Rygel is a royal slug, who eats a lot (and has helium flatulence, but we don't need to get into that. 
)
Check it out: www.farscape.com