Thanks for the replies.
The Brycon should get to 12" (apparently) if it is a Melanopterus however there are a few species that are very similar and given the growth rate of this chap it's possible he coud get much bigger...
The Chalceus should still be growing- there are reports of them reaching 12" but i'd imagine that being in an aquarium sub 300g stunts them.
I'll try to do a full tank shot; i'm going to try and do some dercent shots of the other occupants- the geo's are really becoming beautiful.
Thanks again.