You can start offering fish to your baby at around 6 months of age, as soon as they begin eating solid foods. Fish is one of the most nutrient-dense first foods you can choose. It provides omega-3 fatty acids (especially DHA), which support brain and eye development during a period of rapid growth. The key is picking low-mercury varieties, preparing them safely, and watching for signs of an allergic reaction.
When to Start
The FDA recommends introducing fish once your baby is about 6 months old, alongside other complementary foods that supplement breast milk or formula. There’s no benefit to waiting longer. In fact, the American Academy of Pediatrics reversed earlier guidance that had recommended delaying allergenic foods like fish until age 3 for at-risk children. The current consensus is that there’s no good evidence for holding off past 4 to 6 months.
Your baby should be showing the usual signs of readiness for solids before you offer fish or anything else: sitting upright with support, showing interest in food, and having lost the tongue-thrust reflex that pushes food back out of the mouth.
Best Fish Choices for Babies
Mercury is the main concern when choosing fish for an infant. Babies are small, and their developing nervous systems are more vulnerable to mercury’s effects. Stick to fish from the FDA’s “Best Choices” category, which have the lowest mercury levels. Good options that are also widely available and easy to prepare include:
- Salmon: High in DHA, mild flavor, soft texture that purees well
- Cod: Very mild, white, flaky flesh that most babies accept easily
- Tilapia: Affordable, low-mercury, and neutral-tasting
- Pollock: Another mild white fish, commonly used in frozen fish products
- Sardines: Extremely high in omega-3s, easy to mash from the can
- Trout (freshwater): Good omega-3 content with very low mercury
- Sole and flounder: Thin fillets that cook quickly and flake apart easily
Other low-mercury options include haddock, herring, catfish, whitefish, and canned light tuna (skipjack). Shrimp, crab, and scallop also fall in the “Best Choices” category.
Fish to Avoid
Some large, long-lived predatory fish accumulate high levels of mercury and should not be given to babies or young children. Skip shark, swordfish, king mackerel, tilefish (from the Gulf of Mexico), marlin, orange roughy, and bigeye tuna. These species sit at the top of the ocean food chain and concentrate mercury from everything they eat over their long lifespans.
How to Prepare Fish for a Baby
Remove all skin and bones before serving, including the tiny pin bones that hide inside the flesh of many fillets. Run your finger along the fillet to feel for them, and pull them out with tweezers or small pliers. Even very small bones can be a choking hazard for an infant.
For babies around 6 to 8 months, cook fish thoroughly (bake, steam, or poach) and then puree or mash it. You can thin the puree with a bit of breast milk, formula, or water if it’s too thick. Mixing it with a vegetable puree your baby already enjoys, like sweet potato or butternut squash, can help with acceptance.
Between 8 and 10 months, once your baby is handling soft finger foods, you can serve small, bite-sized pieces of cooked fish instead. The flesh should flake apart easily and feel soft enough to squish between your fingers. Avoid breaded or fried preparations, which add unnecessary salt and make it harder to check that the fish is fully cooked through.
For baby-led weaning from 6 months, some parents offer a large, soft piece of fish (about the size of an adult finger) that the baby can grip and gnaw on. The fish should be cooked until it falls apart with minimal pressure.
Finfish vs. Shellfish
Fish and shellfish are actually separate allergens, so being allergic to one doesn’t automatically mean a reaction to the other. Both can be introduced early, but there’s a reason some parents start with finfish like salmon or cod first. Some research has found that prenatal shellfish consumption (as opposed to finfish) was associated with a higher risk of food allergy in early childhood. The relationship between shellfish and allergy risk in infants is still being studied, but starting with a mild finfish and introducing shellfish separately a few days later is a reasonable approach that lets you track any reactions clearly.
Watching for Allergic Reactions
Fish allergy is one of the more common food allergies, and reactions can range from mild to severe. When you first offer fish, give a small amount on its own, without introducing any other new food that day. Then watch your baby for the next few hours.
Signs of an allergic reaction include hives or red, blotchy skin, swelling around the lips or eyes, vomiting, diarrhea, or wheezing and coughing. In rare cases, a more serious reaction can cause difficulty breathing or sudden limpness. If you see hives and breathing changes together, that’s a medical emergency. Fish allergens can even pass through breast milk: there are documented cases of breastfed infants developing hives and wheezing after their mother ate fish, so a reaction doesn’t require direct contact.
If your baby tolerates a small first taste without issues, gradually increase the portion over the next few servings. Once fish is established as a safe food, aim to include it regularly, about one to two times per week, to provide consistent omega-3 intake during this critical window of brain development.
How Much Fish to Serve
Babies don’t eat large portions of anything, so don’t worry about hitting a specific ounce target at first. A tablespoon or two of pureed fish is a reasonable starting amount for a 6-month-old. By 8 to 10 months, a serving might be about 1 ounce (roughly two tablespoons of flaked fish). The FDA recommends two servings of low-mercury fish per week for young children. At this age, the goal is regular, small exposures rather than large portions.
Canned fish like sardines or canned light tuna can be a convenient shortcut. Choose varieties packed in water with no added salt, or rinse them before serving. Canned salmon with the bones removed (or with soft, edible bones mashed in) is another easy option that requires no cooking.
Tips for Picky Eaters
Fish has a distinct smell and flavor that some babies reject at first. This is normal. It can take 10 to 15 exposures before a baby accepts a new food, so don’t give up after one or two attempts. Try mixing fish into foods your baby already likes: stirred into mashed avocado, blended with sweet potato puree, or folded into soft rice. Mild white fish like cod or tilapia tends to be the easiest sell because it has less of the “fishy” taste that stronger varieties like sardines or mackerel carry. Starting with a milder option and working toward stronger-flavored fish over time gives your baby a chance to adjust gradually.