I have recently been offered a one-off gold panchax.

Basically... What on earth is this fish? I'm told its a Killifish but these aren't very well known where I'm from. I've never seen one before.

I've looked up a bit about it on the internet but personal experience would be great. I've only been offered one -- do they live happily on their own? How big do they grow? What are some suitable/unsuitable tank mates, etc?

Please and thank you. :)