Baby Poop Smell Like Fish (Explained)

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Wondering why your baby’s poop smells like fish and looks green and sometimes sticky?

Generally, baby poop may smell like fish because of an underlying medical issue, such as an infection, allergic reaction or a digestive issue. 

You should be concerned if your baby is showing other symptoms that I am going to talk about in this post. But if your baby is doing fine and gaining weight, there’s nothing to worry about and the smell would usually go away in a few days.

Also Read:Best Diaper Rash Creams For Newborns

Get rid of that nasty diaper smell with a diaper pail and deodorizer!

How Does Baby Poop Normally Smell?

A healthy baby’s stools have typical texture, color, and smell, depending on whether they are being breastfed, formula fed, or being weaned already. 


A baby who is exclusively breastfed will pass mostly odorless stool, while a formula-fed baby’s poop would be slightly smelly.

Also Read: Baby poop smells like yogurt 

Stools will start getting smellier when weaning is started. And certain foods, like garlic in a baby’s or a breastfeeding mother’s diet, and teething can make baby poop smell stronger.

However when a baby’s poop shows significant differences in these characteristics, it might be an issue of concern. 

Reasons Why Baby Poop Smells Like Fish

When a baby passes stools that are very potently smelly, like fish or rotten eggs, it can be a medical problem like a disease or it could be something like bowels moving too quickly and resulting in poor absorption.

If your baby is teething, it could also be the reason why poop has a fishy odor. 

If your baby’s poop smells like fish, careful observation for other tell-tale signs will help to determine if and what kind of medical problem it is and do what is needed to help the baby. 

Reasons Why Baby Poop Smells Fishy


Let’s have a look at the kind of conditions that can result in fish-smelling poop in babies.

Also Read: Why does baby formula smell so bad?

Cholera

Cholera is an illness caused by the bacteria Vibrio cholerae infecting the intestine. The bacteria is introduced to the body by consuming contaminated food or water. It is common in Latin America, South, Asia, and Africa, but rare in the developed world. 

While Cholera can make a baby’s stools smell like fish, there are other symptoms to look for too, such as,

  • Stomach ache
  • Vomiting
  • Watery diarrhea, a.k.a. rice water stools

Most children who get cholera will get over that with mild to moderate upset stomachs, but severe cases can cause dehydration and that can be fatal.

So, if your baby’s fish-smelling poop is accompanied by those other symptoms, seek medical help at once. 

Salmonellosis

Salmonellosis, an infection of the intestine caused by Salmonella bacteria can make a baby’s stools smell like fish too. One can get Salmonellosis by ingesting contaminated water or food, especially raw or undercooked eggs, meat, poultry, or unpasteurized milk. 

Major symptoms of Salmonellosis are,

  • Watery diarrhea, sometimes bloody
  • Vomiting 
  • Fever
  • Stomach cramps
  • Headache

Seek medical help immediately if your baby shows these signs.

While many babies recover from Salmonella infection on their own, others may be prone to dehydration and if the infection spreads beyond the intestine it can be more dangerous.

Lactose Intolerance

Lactose intolerance is the inability to digest lactose, which is a sugar found in milk, due to insufficient production of the enzyme lactase in the body.

Lactose Intolerance


Even though congenital lactose intolerance is rare, it is still a possibility. This can cause foul-smelling stools and other symptoms such as,

  • Diarrhea
  • Bloating
  • Gas
  • Stomach cramps

Seek medical help for a proper diagnosis if the condition continues. A Dr might suggest that you will have to feed your baby a lactose-free formula or a milk substitute if they are lactose intolerant. This should only be decided by a Dr.

Rotavirus Infection

Strong, fish-like feces odor can be a symptom of rotavirus infection. Fever, nausea, and cramping in the abdomen are other symptoms.

This occurs frequently in infants and can occasionally result in serious illness. This is present on contaminated everyday objects, including toys, changing tables, and doorknobs, among others. 

Rotavirus can also spread through contaminated food and water consumption.

Early in infancy, though, this can be avoided. Babies under 6 months of age are frequently given a 2-dose rotavirus vaccination.

PS. The vaccine could sometimes cause fishy order as well.

Giardiasis

Giardiasis is an illness caused by the microscopic parasite Giardia intestinalis. It can be contacted person to person and by contaminated food and water.

Also Read: Accidentally gave baby tap water

Most children with Giardiasis do not show any symptoms. Others can have fish-smelling stools and,

  • Watery diarrhea
  • Abdominal pain
  • Gas
  • Bloating
  • Poor appetite 

Seek medical help if your baby is showing these symptoms, Giardiasis can lead to dehydration.

Bottom Line

If a baby’s stools have a foul, fish-like smell, it can be a sign of a medical issue, such as, bacterial, viral, or parasite infection or, on rare occasions, congenital lactose intolerance.

If you notice your baby’s poop smell like fish, look for other symptoms such as watery and, or bloody diarrhea, vomiting, fever, poor appetite, gas, bloating, abdominal cramps, etc, and seek medical help if there are.

But if your little one is not showing any of these symptoms, there’s nothing to worry about! Even if there’s hair baby poop, it’s ok.

But IMHO, you should always contact your doctor if you notice any unusual changes in your baby’s poop. 

FAQs

Is it normal for baby poop to smell like fish?

No, it is not normal for baby poop to smell like fish. If your baby’s stool has a fishy odor, it could be a sign of an underlying health issue, like a bacterial infection. It is always best to consult with your doctor.