Yup, that's an Arapaima gigas, also known as a pirarucu. It's the same picture I posted before. For more information on this fish, you can look at here:
http://animaldiversity.ummz.umich.edu/site/accounts/information/Arapaima_gigas.html

It's one of the world's largest fishes. It's also a CITES Appendix II listed animal ... :(

What a cool fish market - I would have loved the opportunity to have walked around. :)

Masaki