In a saucepan, heat the water with the milk, salt, sugar and butter.
As soon as it starts to boil, remove from the heat and add the flour all at once.
Mix for 2 to 3 minutes to dry the dough.
Transfer the dough to a bowl and add the beaten eggs one by one, incorporating the eggs well between each addition.
Poach small fish-shaped puffs on a baking tray lined with baking paper, spacing them sufficiently.
Sprinkle with sugar pearls and a chocolate chip for the fish eye.
Bake at 160°C for 30 to 35 minutes.