Barra de Santiago is a fishing village. The morning boats come in around 5–7 AM with whatever is running — usually corvina (snook), róbalo (sea bass), or smaller catch. Several family-run comedores along the beach buy the fish straight off the boats and cook it for lunch.
Whole fried fish, served with white rice, beans, a simple tomato-cucumber salad, two tortillas, and a wedge of lime. Around $8–12 per plate, cash only at most. No printed menu — the day's catch IS the menu. Ask for ceviche if it's running — same fish marinated raw in lime juice with onion, tomato, and chile.
Lylli will point you to her current preferred comedor on arrival — the village is small enough that you can walk past three or four and pick.