Bangkok's Chinatown is full of fish stomach sellers. These dried stomachs have a similar texture to pork crackling (fried pork skins) and are used in Thai & Chinese soups (see fish stomach soup) and add crunch to gop gam dishes (a gop gam dish is a snack dish served as a side dish to a drink of beer or whiskey).
Don't they look like some variety of giant golden rice cracker? By the way the prices shown in the above photo are per 100 gms, not per kilo.
They do wholesale too, although this store was happy to sell me 100 gms to cook with, it normally sells much larger quantities to restaurants.
The street at 13.741541°N 100.506040°E has a good selection of wholesale and retail fish stomach sellers.