Hi Hobbitfeet,
Yellow Tail are know locally as Ekor Kuning, which strangely enough is the direct translation for Yellow Tail, they are a salt water fish about 8 inches long, and I believe are related to Tuna.
Djambal is a type of catfish which although native to Indonesia, was introduced into intensive fish farming, or to give it it's fancy phrase aquaculture around the 1990's but is still rather rarely seen for sale as far as I am aware. The more commonly sold Catfish is called Ikan Patin, Patin being I think a local dialect name for 'yellow tail'.
Both catfish are freshwater fish and the flesh of the Patin is white, reasonably firm, closely grained and is quite sweet, really rather nice actually cooked in the indonesia style which involves simple removal of the gut tract, a cursory clean, followed by total immersion in boiling hot oil, head, fins, tail, and all!
Served with Nasi Puti (steamed rice), Tempe Goreng (fried soy bean cake), Lalap (raw salad vegetables comprising, white cabbage, cucumber, green beans, lettuce and basil) and a small bowl of Sambal Terasi ( hot chilli paste with fermented shrimp and lime juice), all eaten with the fingers it is a wonderful, wonderful evening meal, not too heavy but satisfyingly fulfilling and spicy.
I have made myself hungry just typing this post, but being in Africa for another week, I guess I will just have to wait!