well a month on and i still have him, he has grown stupidly fast, nearly 2" in a month and fattened up loads, he is now the biggest fish in the tank (overtaking loads of other cichlids) and he is completely docile and still behind the Texas and GT in the pecking order by far.
I have a feeling he might be a Syns after all :S he never interacts with anything, not even new additions.