Flake the cooked fish into a large bowl.
Add mashed potatoes and mix well.
Stir in chopped onion and minced garlic.
Beat the egg and add to the mixture.
Season with salt, pepper, and parsley.
Form the mixture into patties.
Coat each cake in breadcrumbs.
Heat oil in a frying pan over medium heat.
Fry the cakes for about 4-5 minutes on each side until golden brown.
Remove from the pan and drain on paper towels.