Step 1
Combine stock, rice, wine, ashwagandha, kombu, bay leaves, and hijiki in a clay pot or small Dutch oven. Season lightly with salt, depending on whether your stock is already seasoned (it reduces as the dish cooks, which will concentrate the saltiness). Bring to a boil, then reduce heat to low. Stir once, cover, and cook, maintaining an active simmer, until rice is nearly tender and stock is almost completely evaporated, 40–50 minutes (if dry, you can add water by quarter-cupfuls if needed, or, if soupy, simmer uncovered until rice is nearly dry before proceeding).
Step 2
Season fish with salt. Uncover pot, lay mushrooms over rice mixture, then lay fish, skin side up, over mushrooms. Cover pot and steam until fish is opaque and rice is beginning to crisp on bottom of pot, 6–8 minutes.
Step 3
Scatter pea shoots around fish and top with radishes and mint. Serve right from clay pot.