Review scope

This summary is based on the published abstract. We have not appraised the full methods, tables or supplementary material. Details absent from the abstract remain unverified.

Question and design

Goldfish fingerlings in a controlled feeding experiment. Four digestible-protein levels from 28% to 49%, at two digestible-energy levels. Comparator: The alternative protein and energy combinations.

What was measured?

Growth, feed conversion, protein efficiency and energy retention.

Main findings

Most performance measures depended on both protein and energy. Growth generally favoured 3,200 over 3,600 kcal/kg; fitted optima differed by outcome.

Study strengths

Factorial design tests protein and energy together.

Limitations

Juvenile growth under experimental conditions. Digestible protein is not the crude-protein percentage on a typical retail label.

Researchers’ conclusion

The authors proposed approximately 38–40% digestible protein at 3,200 kcal/kg under their conditions.

Evidence.pet interpretation

This cannot be transferred directly to adult maintenance or other fish species. More labelled protein does not automatically mean a better food.

Funding and conflicts

Not verified from the abstract; full declarations have not been reviewed.

Source and review date

Souto CN et al. Protein to energy ratios in goldfish (Carassius auratus) diets. Ciência e Agrotecnologia. 2013;37(6). DOI: 10.1590/S1413-70542013000600008.

Read the primary source · DOI record

STU-043. Reviewed 25 September 2026. Next review 25 December 2026.