What fish is best to give a baby?

Well-cooked, boneless fish that is low in mercury is the usual starting point for a baby. We shopped from the Best Choices end of the FDA and EPA advice about eating fish: salmon, sardines, cod, pollock, trout, flounder and tilapia. We cooked the fish until it flaked apart under a fork, flaked it fine, and stirred about a teaspoon through a puree our baby already knew.

Which fish should babies avoid because of mercury?

Big, long-lived, predatory fish build up the most mercury, so they are left off a baby's plate. FSANZ mercury advice singles out shark (flake), billfish (swordfish, broadbill and marlin), orange roughy or deep sea perch, and catfish. The FDA and EPA Choices to Avoid list includes shark, swordfish, marlin, king mackerel, tilefish, orange roughy and bigeye tuna. Raw fish, raw shellfish and smoked fish were also not first-year foods for us.

How do I check fish for bones before giving it to my baby?

Flaking the cooked fish apart with clean fingers over a plate is the most reliable way we found to check for bones, because fingers find bones that a fork pushes straight through. Do it twice, in good light. Mash tinned salmon and sardines thoroughly, since their soft bones are not smooth. Check fillets sold as boneless too: we found bones in two of them. Check prawns for shell and tail fragments.

Can I introduce fish and shellfish to my baby at the same time?

No, fish and shellfish are best introduced separately, with a clear gap between them. We gave fish its own 14 days first, then started again from day 1 with well-cooked, finely chopped prawn, with no other new foods in either window. Running them back to back would have made it impossible to say which one caused a reaction, and some reactions are not immediate. Ask your paediatrician to sign off on the plan.

Introducing Fish and Shellfish to Your Baby

We ticked “seafood” off in our heads after our baby ate salmon twice without a murmur, and then our paediatrician pointed out that we had introduced exactly one allergen, not two. Fish and shellfish are counted separately on every allergen list we looked at, and a baby who is fine with salmon has told you nothing at all about prawns. So we went back and did it properly, weeks apart. What follows is what worked for our family. Your doctor knows your baby and should be the one to sign off on the plan.

Direct Answer: Fish and shellfish are separate allergens and are introduced separately. Current guidance is to offer common allergens from around six months, once a baby is developmentally ready, starting with well-cooked, boneless, low-mercury fish such as salmon, cod or sardines flaked into a familiar purée, then well-cooked finely chopped prawn as its own later introduction. Raw fish, raw shellfish and high-mercury species are left out.

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Two allergens, not one

Every regional list we checked splits seafood up. The US FDA list of nine names fish and crustacean shellfish as two separate entries. The EU list of 14 goes further and splits it three ways: fish, crustaceans, and molluscs. Australia and New Zealand do the same. That is not a labelling technicality. A baby who eats cod happily has been introduced to fish and to nothing else.

Shellfish also behaves differently over time. It is diagnosed more often in older children and adults than in infants, and it tends to persist rather than fade the way egg and cow's milk allergies frequently do. None of that is a reason to delay it. It did make us stop treating "seafood" as one box to tick and give each one its own run.

The fish we started with

Well cooked, boneless, and low in mercury. Salmon first, then cod, then hoki, then tinned sardines mashed through a vegetable purée our baby already ate without trouble. The FDA and EPA advice about eating fish sorts species into Best Choices, Good Choices, and Choices to Avoid, and we shopped off the Best Choices end of it: salmon, sardines, cod, pollock, trout, flounder, tilapia.

We cooked it until it flaked apart under a fork, then flaked it fine and stirred about a teaspoon through something familiar so the texture was the only new thing. Current allergy-prevention guidance, including ASCIA's infant feeding and allergy prevention advice, favours introducing common allergens from around six months once a baby is developmentally ready, and then keeping them in the diet regularly. Babies with severe eczema or an existing food allergy get a tailored plan from their doctor instead.

What we left off the plate

Mercury was the one non-allergy thing we paid attention to. FSANZ mercury advice singles out shark (flake), billfish (swordfish, broadbill and marlin), orange roughy or deep sea perch, and catfish for tight limits in young children, because big, long-lived, predatory fish accumulate the most. The FDA and EPA Choices to Avoid list overlaps almost exactly: shark, swordfish, marlin, king mackerel, tilefish, orange roughy, and bigeye tuna.

We also skipped raw fish and raw shellfish entirely, and smoked fish, which is both a listeria consideration and very salty for a baby's kidneys. NHS guidance on foods to avoid giving babies covers the same ground. None of these are forever rules. They are just not first-year foods, and none of them are needed to introduce the allergen.

Bones were the risk we lost sleep over

The allergy part of fish made us nervous in theory. The bones made us nervous in practice. A fish bone is small, pale, and easy to miss in a white fillet, and it is a genuine choking hazard rather than a theoretical one.

What we settled into: cook the fillet, then flake it apart with clean fingers over a plate rather than chopping it with a fork, because fingers find bones that a fork pushes straight through. Do it twice, in good light. Tinned salmon and sardines have soft edible bones, but soft is not the same as smooth, so we mashed them thoroughly rather than leaving vertebrae intact. With prawns we checked for shell and tail fragments the same way. Boneless fillets sold as boneless still get checked. We found bones in two of them.

Fish first, prawns as their own introduction

We used the same rhythm we used for peanuts. Day 1, a teaspoon of flaked salmon through a familiar purée, early in the day, at home, with nothing else new on the menu. Day 3, a slightly larger amount. Day 7, a proper portion. Day 14, fish as an ordinary part of meals a couple of times a week, which is the part that matters for keeping the allergen in the diet.

Then we left a clear gap and started again from day 1 with well-cooked, finely chopped prawn. Same two weeks, same no-other-new-foods rule. Running them back to back would have left us unable to say which one caused anything, and some reactions are not immediate, which is the whole point of the observation window.

What we wrote down

Two overlapping 14-day windows across two allergens is more than we could hold in our heads, particularly with a nanny and two grandparents feeding our baby on different days. We logged each offer with a timestamp, the amount, and how it went, and let the app's reminders tell us which day of which schedule we were actually on.

Nothing happened, in the end. Both went in uneventfully. But when the paediatrician asked at the next appointment what our baby had eaten and whether we had seen anything at all, we had an answer with dates on it instead of a vague "the salmon was fine, I think". That was worth the small effort of writing it down at the time.