Hikari-mono

Silver-skinned fish like horse mackerel is called "Hikari-mono" in Japan.

 Its taste is more rich than that of white fish.

 If you want to eat the fresh one, you should go to the Tsukij fish 

market in the evening because Hikari-mono fishes are brought to the market about those time.

more info:
  http://en.wikipedia.org/wiki/Horse_mackerel
(wikipedia)