Low Carb Fish Tostada with Avocado Tartar Sauce

Low Carb Fish Tostada (Tostada de Pescado) – a perfect snack meal! Ours is so tasty using Avocado Tartar Sauce with Pickled Jalapeños as its base. To keep it low carb, we use our quick and easy low-carb taco shell. All that is left is to feature a perfectly grilled fish of your choice and delicious Mexican toppings.

Tostada is Spanish for “toasted.” It generally refers to a flat tortilla that is deep fried and crispy. Frying briefly will turn a tortilla into a golden, rigid, and crunchy toasted tortilla chip that is a perfect tostada. Yes, it is the same corn or flour tortilla that we fold and call a taco. You can make this same recipe in the shape of a taco and have delicious “Baja-style” fish tacos without breaded fried fish.


The choice of fish is up to you. Everyone has their favorite – I like a thin fillet of cod – a white fish. It grills quickly and has a mild flavor that will not overpower toppings. If you like a stronger flavor, a chunky Halibut is a great choice. Mahi Mahi is a typical fish used in fish tacos and although pricier, it is delicious. Any fish will do and for some (like Joanie) a grilled salmon or swordfish would be a delicious choice!

Fish Tostada with Avocado Tartar Sauce

The key flavor component to this recipe is our delicious Avocado Tartar Sauce with Pickled Jalapeños. You could substitute a regular tartar sauce, if you prefer, but give our avocado tartar a try – it is delicious!

Toppings are your choice. We prefer the usual Mexican ingredients that keep the dish low carb. Red cabbage adds a needed crunch and red onions have a stronger flavor that pairs well with the lighter fish flavor. Lime juice adds a citrus tang, and queso fresco and Mexican cream balance everything! Cilantro is the perfect garnish. We often use a few chopped tomatoes or a teaspoon of salsa for even more flavor.

Preparation Tips

We grill white fish in butter, it cooks quickly, and we do not worry if it breaks into pieces when flipped. After all, I use small pieces or chunks for the tostada. We season with salt and pepper and like a sprinkle of smoked paprika on both sides near the end of the grilling process. Grill marks are not needed, but you can also use blackened fish if you like that smoky flavor.

Joanie made her salmon in the oven with a tenting process to steam her fish to perfection. Her technique is very similar to her Oven Baked Salmon with Chipotle Salsa. Her salmon is the fish of choice for her tostada. That is the beauty of the recipe. Even using leftover fish is perfect for this delicious tostada snack meal.

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We start with a spread of the Avocado Tartar Sauce as the base on top of our fried tortilla. You will usually see refried beans as the base. The purpose is the same. It serves as the glue to hold your ingredients. Our avocado tartar sauce is healthier and tastier!

Ordering of Toppings

The rest of the process is simply ordering the toppings. We like the next to include the red cabbage since we like the crunch intermingled with our delicious grilled fish. It is also cold, so that hot-cold mix is a big part of the taste. Squeeze some lime juice right after adding the grilled fish so it absorbs that typical citrus flavor. Red onion comes next and crumbled cheese will fall through the tostada.

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Finally, the garnish of Mexican cream is a nice choice and sprinkled chopped cilantro completes the presentation and blend of Mexican flavors. You will have a visually pleasing, crunchy, hot and cold blended snack meal for any festive day of the week.

Picual Extra Virgin Olive Oil by José Andrés Foods
  • Elegant, extra virgin Picual olive oil
  • Vigorous olive oil with a peppery finish

Low Carb Fish Tostada

You may have heard of the traditional “Taco Tuesday” featured at bars and restaurants throughout the Southwest. Let’s feature our Low Carb Fish Tostada and call it “Tostada Thursday!” Regardless of your day of the week, this recipe passes the Tasty Low Carb test!

Low Carb Fish Tostada with Avocado Tartar Sauce

Recipe by Joanie and Chris
5.0 from 15 votes
Course: Snack Meals, Fish and SeafoodCuisine: Mexican


Prep time


Cooking time




Net Carbs


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Only 6g of net carbs in this delicious Fish Tostada. A perfect snack meal using our Low-Carb Taco Shell and Avocado Tartar Sauce with Pickled Jalapeños.

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  • Tostada Shell
  • 1 1 Taco shell low carb

  • 2 tablespoons 2 tablespoons Olive oil extra virgin

  • Grilled Fish Tostada
  • 4 ounces 113 g Fish (Cod, Salmon, Mahi Mahi or Halibut) grilled or baked

  • 2 tablespoons 2 tablespoons Avocado tartar sauce

  • Red cabbage shredded

  • 1 tablespoon 1 tablespoon Queso fresco crumbled

  • 1 teaspoon 1 teaspoon Red onion diced

  • 1 teaspoon 1 teaspoon Lime juice fresh

  • 1 ounce 1 ounce Mexican cream

  • 1 teaspoon 1 teaspoon Cilantro chopped


  • Tostada Shell
  • Heat olive oil in a small skillet on medium heat, until hot. Cook low-carb taco shell for 1 minute, flip and cook for 1 more minute. Place on cooling rack until cooled.
  • Grilled Fish Tostada
  • Spread avocado tartar sauce on tostada shell. Top with a small amount of red cabbage, red onion, and hot grilled white fish chunks. Squeeze 1 ounce of fresh lime juice next, sprinkle with crumbled queso fresco and drizzle with Mexican cream. Sprinkle with chopped cilantro and serve.


Chef’s Notes

  • You can also use some chopped tomatoes or a teaspoon of salsa as a topping.

Nutrition Facts

  • Calories: 401.4kcal
  • Carbohydrates: 7.4g
  • Protein: 4.4g
  • Fat: 38.6g
  • Saturated Fat: 6.6g
  • Trans Fat: 0g
  • Cholesterol: 25.2mg
  • Sodium: 267.8mg
  • Potassium: 56.4mg
  • Fiber: 0.9g
  • Sugar: 1.6g
  • Vitamin A: 700IU
  • Vitamin C: 17mg
  • Calcium: 142.6mg
  • Iron: 2.1mg

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