He really is stunning
- you sure its a he?
I hope you have a big tank there as they grow to 20 cm and will eat smaller fish such as tetras when fully grown!
LOL, they can grow far in excess of 20cm, they wont eat smaller fish or any fish at all (not sure where you got that from) unless it has already died first and then feeds of there carcess. They are omniverous and usually eat bio-film and organic matter with varied veg etc etc.
To the OP he is really a stunner and youve picked a lovely species to keep
They can grow bigger in the wild but 20 cm or 8 inches is the usual size for captive ones.