The fish may need freezing for 3 days to make it safe to eat. Check with your local fish monger. If that is the case, place it in the freezer for 3 days, then thaw it and use.
Peel and finely chop the shallots. Finely chop the chili pepper.
Peel and dice the mango in 0.5 inch cubes.
Remove any skin from the fish, and dice in 0.5 inch cubes.
Distribute all fish, mango, onion, pepper evenly in small serving bowls/glasses. Squeeze all lime juice from the limes and distribute the juice evenly in the bowls. Stir gently, and then cover them with saran wrap and leave in the fridge for 1 hour.
Take the bowls/glasses out from the fridge and add salt to taste. Add plenty cilantro for decoration and flavor and serve.