Mala Leatherjacket Fish

Haoryu ("mouse fish") is the Chongqing dialect name for the leatherjacket, or filefish — properly the green-finned leatherjacket, also sold as horsehead fish, rubber fish or peel-off fish. Once dressed the way Chongqing kitchens take it — head, tough hide and innards all removed — what is left is a pale white body whose tapering shape was thought to resemble a mouse, and in Sichuan-Chongqing speech a mouse is a haozi, so the fish became the haoryu. It is a sea fish rather than a river fish, and only reached the city in quantity in the late 1970s, when frozen marine catch from the coast began moving inland; locals first met it as cheap, bony-free, easy-to-eat fish and at first hardly knew what to do with it. It entered the Chongqing table through hotpot — dropped in as a cheap add-in — and from there grew into a dish in its own right, cooked dry-pot, boiled mala-style, deep-fried or grilled. As a modern jianghu dish it has no single recorded inventor; it is documented as a Chongqing restaurant staple, sibling to dry-pot frog, dry-pot chicken and the other dry-pots.

The fish goes in as short white segments and comes out seared at the edges, the firm flesh staying in clean meaty chunks rather than flaking apart — there are no fine pin-bones to pick, just the one soft central spine you eat straight around. Each piece is glazed in red oil and clinging dried chili, the pickled chili lending a sour-bright edge over the dry heat. The chili burn lands first; the peppercorn's fine numbing buzz climbs the tongue a beat later. The little brazier keeps it sizzling, so the sauce thickens and darkens as you eat, and the potato and lotus root underneath drink up the best of the oil.

Leatherjacket flesh is firm and low in fat with no intramuscular pin-bones, which is exactly why it can take a hard dry-pot frying that would shred a softer river fish — the chunks hold their shape through repeated tossing instead of falling to mush. The fish is usually patted in a little starch and run through hot oil first to set the surface and seal the cut faces, so it survives the long stir-fry still juicy; the chili bean paste must be fried in oil until it stains the fat red and turns fragrant before the fish returns, which kills its raw edge and releases both the color and the bean aroma. Dried chili gives the heat, Sichuan peppercorn the numbing tingle — its hydroxy-alpha-sanshool acting on the tongue's touch nerves so the "ma" is felt as a fine buzz rather than tasted; pickled chili and pickled ginger shift the base toward a sour-fresh note rather than flat dry heat. The whole point is a reduced, not soupy, sauce: the liquid is cooked off so the seasoned oil clings to the fish, and at the table the low flame keeps evaporating the last of it so the glaze stays on the meat instead of pooling in the pot — the defining behavior of a dry-pot.