Onion + Fish
A good pairing. Cooks put them together in 1,924 recipes, and they share 41 flavor molecules: the top 19% of all ingredient pairs.
Do onion and fish go together?
Yes. 1,924 recipes in our collection combine them, and they share 41 flavor molecules. That places them in the top 19% of every ingredient pair we score.
Why they work
They overlap on 41 flavor molecules: 26% of fish's 158. Among the shared key aromas are 2,4-decadienal (seaweed) and decanal (soap, orange peel). Most of what they share is background chemistry many foods carry, so the overlap does little for the smell.
What each one brings
onion
The savoury side. Savory notes make up 8% of its labelled aroma molecules, against 0% for fish. It carries 324 molecules fish doesn't have.
fish
The fresh, green side. Green notes make up 20% of its labelled aroma molecules, against 8% for onion. It carries 117 molecules onion doesn't have.
Add a third ingredient
- Potato: the best fit for both, top 3% of pairs with onion, top 15% with fish.
- Common carp: top 11% of pairs with onion, top 7% with fish.
- Garlic: top 1% of pairs with onion, top 27% with fish.
- Atlantic herring: top 7% of pairs with onion, top 13% with fish.
Ranked by the average of its two pairing scores. Only foods used in at least 100 recipes are suggested.
Recipes with onion and fish
Almost always mains: 75 of the 85 recipes with a course label are mains.
Can you swap one for the other?
Not really. Each has a lot the other lacks: onion has 324 molecules fish doesn't, and fish has 117 that onion doesn't. Treat them as partners, not stand-ins. This compares flavor only; texture, moisture and the job each does in a dish matter too.
All 41 shared molecules
See every shared molecule grouped by chemical class, with key aromas marked, plus the 324 only in onion and the 117 only in fish.
Onion and fish questions
Do onion and fish go together?
A good pairing. Cooks put them together in 1,924 recipes, and they share 41 flavor molecules: the top 19% of all ingredient pairs.
Why do onion and fish taste good together?
They overlap on 41 flavor molecules: 26% of fish's 158. Among the shared key aromas are 2,4-decadienal (seaweed) and decanal (soap, orange peel). Most of what they share is background chemistry many foods carry, so the overlap does little for the smell.
What goes with onion and fish?
Potato is the best third ingredient: top 3% of pairs with onion and top 15% with fish. Common carp and garlic also fit both.
What can you make with onion and fish?
Almost always mains: 75 of the 85 recipes with a course label are mains. Common dishes include Fish Chowder, Fish Calulu, Fish Tacari, Fish and Vegetable Stew.
Can I use fish instead of onion?
Not really. Each has a lot the other lacks: onion has 324 molecules fish doesn't, and fish has 117 that onion doesn't. Treat them as partners, not stand-ins. This compares flavor only; texture, moisture and the job each does in a dish matter too.
Compare other ingredients
Ranks compare this pair with 20,000 random ingredient pairs on CompKitchen. Molecule counts are what the studies and databases we aggregate have reported for each ingredient: a measure of coverage, not a full census. How we score pairs
Cite this analysis
Compound Kitchen (2026). Compound similarity analysis: Onion vs Fish. https://compkitchen.com/compare/onion-vs-fish. Accessed 2026-11-03.
@misc{compkitchen_compare_compound_similarity_analysis_onion_vs_fish_2026,
title = {Compound similarity analysis: Onion vs Fish},
author = {{Compound Kitchen}},
year = {2026},
url = {https://compkitchen.com/compare/onion-vs-fish},
note = {Accessed: 2026-11-03}
}
Methodology DOI: 10.5281/zenodo.19719459 · CC BY 4.0 · Citations are a request, not a requirement.