Flounder

Flounder, when fully cooked, may be introduced as soon as baby is ready to start solids, which is generally around 6 months of age. Compared to other fish, flounder tends to be relatively low in mercury and can be offered up to a couple of times a week.  

Flounder is the common name for a group of bottom-dwellers called flatfish. There are numerous species of flounder that make their home near the muddy or sandy floors of bodies of fresh and salt water around the world. The group’s biodiversity and geographic reach has resulted in many names for the fish, including hirame or karei, particularly when the fish is used in sushi. Flounder’s similarity to other flatfish like sole and plaice sometimes leads to confusion or mislabeling when the fish are sold in the marketplace, but all of these fish share similar mild flavor and flaky white flesh when cooked.

Yes. Flounder is high in protein and offers omega-3 fatty acids, lots of vitamin B12, choline, selenium, and vitamin D. Collectively, these nutrients are important for baby’s cardiovascular, immune, bone, and neurological health, as well as cell growth and structure. Importantly, flounder is also low in mercury, a neurotoxin to which babies are particularly susceptible. More on this topic in our guide, Best & Worst Fish for Babies.

Smoked, salted, and some dried flounder products are best reserved for older children and adults, as they can have sodium in excess of baby’s needs. 

★Tip: Check labels on frozen fish and when possible, try to avoid frozen fish with added sodium (including sodium triphosphate). For more on how much sodium babies need, see our Sodium page.

No, however the bones in fresh fish are a choking hazard. To reduce the risk, carefully check cooked fish for any bones and remove them before serving. As always, make sure to create a safe eating environment and stay within an arm’s reach of baby at mealtime. For more information on choking, visit our sections on gagging and choking and familiarize yourself with the list of common choking hazards.

Yes. Finned fish, including flounder, are classified as a Global Priority Allergen by the World Health Organization. It’s estimated that only 0.2 percent of people are allergic to finned fish worldwide, and the prevalence of fish allergies in children, while variable, is even less than in adults. About 40% of people with finned fish allergies don’t experience their first allergic reaction until adulthood. Unfortunately, most individuals who are allergic to finned fish do not outgrow the allergy.

Some individuals with finned fish allergy may react from inhaling proteins that become aerosolized when cooking fish. If this is the case for baby, avoid cooking fish in the household when baby is present.

Around 50% of individuals with one finned fish allergy react to other fish. This is because the major allergen in finned fish, beta-parvalbumin, is present in most fish, regardless of species. Due to cross-contamination and mislabeling of fish, allergists often recommend that those who are allergic to one species of finned fish should avoid all finned fish until meeting with an allergist to determine which fish might be safely introduced into the diet. This is an individualized recommendation, so be sure to confirm with your allergist before offering other finned fish if baby is allergic to flounder.

Finned fish are a known trigger of food protein-induced enterocolitis syndrome, also known as FPIES. FPIES is a delayed allergy to food protein which causes the sudden onset of repetitive vomiting and diarrhea to begin a few hours after ingestion. Left untreated, the reaction can result in significant dehydration. Unlike other food allergens, FPIES to finned fish may not present until later in life, and tends to be life-long.

Lastly, a note on scombroid poisoning, which is sometimes mistaken for fish allergy. Scombroid poisoning is a type of food poisoning that occurs when someone eats fish that has been improperly stored, which allows a large amount of histamine to build up in the fish. When consumed, this large load of histamine can cause symptoms that mimic those of an allergic reaction, causing people to believe that they have developed a finned fish allergy, even if they are not allergic. Ensuring that fish has been stored at adequately cool temperatures can minimize the risk of such a reaction.

If you suspect baby may be allergic to fish, consult an allergist before introducing flounder. As with all common allergens, introduce flounder in small amounts at first and watch closely as baby eats to see if any adverse reaction occurs. If all goes well, gradually increase the serving size over time. Once common food allergens are successfully introduced, it is recommended to keep them in the diet regularly (twice weekly, if possible). However, this doesn’t mean that each different fish species must be offered multiple times a week. Finned fish share the same major proteins, so it is perfectly acceptable to rotate finned fish varieties according to availability and preference.

No. Flounder isn’t generally thought of as a food that promotes pooping, although it can play a role in healthy digestion as part of a varied diet. Diets featuring fish like flounder may promote the presence of beneficial bacteria, like Lactobacillus, which contributes to a healthy gut microbiome. Pooping patterns can vary significantly from child to child, so be sure to talk to your pediatric healthcare provider if you have concerns about baby’s pooping or digestive function.

Never serve raw or undercooked flounder to an infant. Doing so greatly increases the risk of foodborne illness, especially salmonellosis and vibriosis, harmful bacterial infections for babies, children, and adults alike, with more risk of severe symptoms in babies. The risk of severe illness is highest in infants and individuals with complex medical backgrounds, taking stomach acid reducing medications, and/or people who are immunocompromised. Cooking finned fish and shellfish to an internal temperature of 145 F (63 C) kills any bacteria in the food. Ultimately, there is no “best” age to introduce raw or undercooked finned fish and shellfish to toddlers; rather, it is a personal decision for which you must calculate risk.