I think you're right about it not being one of the fish on the site I sent you for all the reasons that you suggest, especially the points about the base colour of the glass, and how it stands. You could add that none of them have a a white eye with a black dot in the middle. Some Altaglass fish do have quite a lot of detail, at least the ones I've seen. However, the main reason that I suggested Altaglass was that I vaguely remembered a similar fish somewhere with a label on. I think it was in a local antique store. I'll check back in the store in the next couple of days to see if it's still there. If it's similar, I'll ask if I can take a photograph.
BTW, how big is your fish? As it didn't get away, I expect accuracy.
Antiquerose: Yours does look like Altaglass, which, given your location, makes sense.