For the fish soup with vegetables, peel and finely dice the onion. Blanch (scald) the tomatoes with boiling hot water, peel, seed and cut into 1/2 cm pieces, removing the stalks. Clean the chili peppers, slice lengthwise, rinse and cut into narrow strips.
Rinse and peel the potatoes and sweet potatoes and cut into cubes about 1 cm. Peel the pumpkin, remove the fibers and seeds. Chop the flesh into small pieces. Peel the banana with a kitchen knife, cut in half lengthwise and slice into slices about 1 cm wide.
Pour the fish broth into a saucepan and add all the prepared ingredients. Peel the garlic clove, squeeze it and add it. Let everything simmer at low temperature with the lid closed for 15 minutes.
Cut the fish fillet into 3 cm pieces. Melt the butter. Fry the fish pieces on both sides until golden brown, then add to the soup. Season with pepper, cumin, salt, Worcester sauce and juice of one lemon.