Low Carb Fish Soup Recipe (3g Net Carbs)
A Mediterranean-style sea bass and vegetable soup at 3g net carbs per serving. Serves 6 with 260 calories, 24g protein, and 14g fat each. Ready in 40 minutes. A clear tomato-broth base with sea bass, leek, fennel, garlic, and a finishing squeeze of lemon. Built for low-carb, keto, pescatarian keto, and diabetic-friendly eaters who want a light dinner soup that reads like a Provencal bourride without the potato or rouille bread.
Why This Works on Keto
Classic Mediterranean fish soups (bouillabaisse, cioppino, kakavia) usually lean on potato or bread croutons to bulk up the bowl. This version drops the starch and leans on aromatics (leek, fennel, garlic) and a small hit of crushed tomato for body, holding total carbs at 3g per serving.
Sea bass adds a full 24g protein at zero carbs and brings vitamins A, B1, B2, B6, B12, and D in one ingredient. Extra virgin olive oil is the fat source rather than heavy cream, which keeps the soup light while still delivering monounsaturated fats.
The Mediterranean method (build a broth with aromatics, add fish last for a brief simmer) keeps the protein tender and prevents the soup from turning into fish paste.
For more on this, take a look at our 1400 calorie low carb meal plan guide.
For more on this topic, check out our guide on dukan diet plan.
Low Carb Fish Soup Recipe
Ingredients
- 1 medium sea bass
- 3 tbsp. olive oil
- 1 celery stalk
- 1 medium carrot
- 1 medium onion
- 1 garlic clove
- 1/2 tsp. coriander seeds
- 6 cups of water
- Fresh parsley 1/2 bunch
- 1 bay leaf
- 1/2 lemon juice
- 1/2 tsp. turmeric
- Salt and pepper to taste
Dressing
- 1 egg yolk
- 1 lemon juice
Instructions
- Remove and clean the bones of the sea bass fish. Transfer the fish to a saucepan and add the cold water. Peel the carrots and onions, then chop them randomly. Chop the celery stalk and add it to the pot along with the chopped vegetables, parsley, black pepper, garlic, bay leaf, lemon juice, turmeric, coriander seeds, salt, and olive oil.
- To obtain a delicious fish broth, boil the fish with the root vegetables and aromatic herbs over medium heat until it releases its essence. Take the boiled fish meat onto a serving plate and shred it into small pieces. Strain the vegetable broth, which takes on the flavor of the fish, through a strainer to obtain a smooth broth.
- Put the fish broth back in the pot and add the fish pieces to it. For the dressing, mix the egg yolk and lemon juice well. While the soup is still hot, add the dressing little by little to the water. Boil on low heat for another 10 minutes with the dressing. Serve hot.
Video
Notes
- To get all the benefits of fish, boil all the pieces of fish in water, then drain.
- Allow small pieces of vegetables to pass through the strainer, as they will add a lot of flavor to the soup.
- You can serve the soup with slices of toasted cheese bread.
- For a thicker soup, you can add 1 tablespoon of flour.
Nutrition
Ingredient Notes
Sea bass (Mediterranean branzino, Chilean sea bass, or American black sea bass) holds structure in a light broth. Cod, halibut, or snapper substitute cleanly. Skip salmon; it is too oily for this style.
Fennel bulb (1 cup sliced, 3g carbs) is non-negotiable for the Mediterranean character; anise seed can supplement if fennel is unavailable. Leek adds allium depth without the sharper hit of onion at 3g carbs per 1/2 cup.
Crushed tomato at 4g carbs per 1/2 cup; use the whole can for 6 servings total to keep individual portions clean. Fish stock beats chicken stock here; Bar Harbor and Kitchen Basics offer canned versions with no sugar added. Fresh lemon at the finish.
Skip bottled lemon juice which flattens the brightness.
On a similar note, our low carb keto diet plan article has more practical tips.
Tips and Variations
Sweat the leek, fennel, and garlic in 3 tbsp olive oil over medium-low for 8 minutes without color. This step builds the aromatic base. Add crushed tomato and cook 3 minutes to concentrate. Pour in 6 cups fish stock, bring to a simmer, cook 15 minutes uncovered so the broth reduces slightly.
Slide 1.5 lbs sea bass (cut into 2-inch chunks) into the simmering broth, cover, cook 6-8 minutes just until the fish flakes. Off heat, add fresh parsley, basil, and 2 tbsp lemon juice. For a dairy-free version, this recipe is already dairy-free.
For a spicier variation, add 1/2 tsp red pepper flakes with the aromatics and 1 tbsp harissa at the finish. For higher-protein, add 12 clams or mussels during the last 5 minutes of cooking. For a heartier bowl, add 1 cup diced zucchini or 1 cup baby spinach in the last 2 minutes.
Serve with a drizzle of good olive oil.
Storage and Reheating
Refrigerate up to 1 day. Fish soup does not hold well beyond that; the fish breaks down and the broth turns cloudy. Reheat gently in a saucepan over low heat for 6 minutes until just warmed through. Do not boil on reheat; the fish will fall apart. Not suitable for freezing.
