# Young Killifish Behavior Predicts How Long They Will Live

_Evidence Level: Preliminary · Bedbrook CN et al., Science (New York, N.Y.), DOI 10.1126/science.aea9795_

*Lifelong behavioral screen reveals an architecture of vertebrate aging.*

- **Evidence Level**: Preliminary
- **Why this grade**: 81 fish were watched over their whole lives; results from fish do not translate directly to people, and the main analyses were in males.
- **Facts**: Design: Animal study · Funding: NIA (NIH), Howard Hughes Medical Institute, Keck, Glenn and Simons…
- **Population**: Animal study
- **Publication Types**: Journal Article
- **Journal**: Science (New York, N.Y.)
- **Sample Size**: 81 male African turquoise killifish
- **Authors**: Bedbrook CN, Nath RD, Zhang L, Linderman SW, Brunet A, Deisseroth K
- **Graded and published**: 2026-03-12
- **Last edited**: 2026-10-19
- **Topics**: Aging Biology, Lifespan, Biomarkers
- **DOI**: https://doi.org/10.1126/science.aea9795
- **Free full text**: https://pmc.ncbi.nlm.nih.gov/articles/PMC13165398/
- **Original Source**: https://pubmed.ncbi.nlm.nih.gov/41818367/

## Summary

The way a young fish moves already says a lot about how long it will live. That is the finding of researchers who filmed killifish for their entire lives. These African fish live only about four to eight months, so a whole life can be watched. A computer program used nothing but the behavior of young fish to predict whether they would be short- or long-lived.

Cameras filmed 81 male fish in separate tanks, from sexual maturity until natural death. Fish that reached at least 200 days counted as long-lived. From 70 days of age, the prediction was right more than seven times out of ten. By 100 days, the fish that went on to live long were more active and swam faster. A behavior-based clock estimated each fish's age to within 12 days on average. Fish on a restricted diet looked 42 days younger than their real age by this clock.

Aging also did not unfold as a smooth decline. The fish moved through about six stable life stages, with sudden shifts between them. The authors note the exact number depends on how the model is set up. The main lifespan analyses used male fish, and a smaller group of females was also tracked. Whether any of this applies to people was not tested.

## Practical Takeaway

In killifish, the behavior of young animals revealed whether they would go on to live a short or a long life.

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_Canonical: https://longevity-germany.com/en/research/young-killifish-behavior-predicts-how-long-they-will-live · Part of Longevity Cities · Updated 2026-10-19_