When in doubt, consult
fishbase.
Ibodai does very closely resemble an American Butterfish (a second cousin). It also closely resembles what is called a Pacific Pompano in some countries. It is not, however, actually in either the Butterfishes (Stromateidae) or Pompanos (Carangidae) family. It is a member of the Medusafishes (Centrolophidae) family which is in the same sub-order as Butterfishes. The Ibodai species (Psenopsis anomala) is peculiar to Japan and the East China Sea. It is called a Melon Seed (which I think is what the Japanese name means in English) or a Pacific Rudder Fish.
http://www.fishbase.org/Summary/Species ... php?id=497
In Viet Nam, an Ibodai is actually called a Japanese Butterfish, however in Japan, "Japanese Butterfish" refers to a different species of Medusafish, and in Australia refers to a species of Whiptail Bream.
It seems that the rounder species of Medusafish are often misclassified as Butterfish. The Blackspot Butterfish, which occurs in the same region, is also not actually in the Butterfishes family but is yet another a type of Medusafish.