Study summary · Goldfish · Live-feed enrichment · Controlled feeding trial
The strongest result came from a combined enrichment
A 90-day goldfish experiment compared a commercial food with the same food plus unenriched or enriched live Artemia. Fish receiving Artemia enriched with both spirulina and canthaxanthin had the highest final weight and favourable colour measures. Spirulina-only enrichment did not significantly increase final weight over the control. This is evidence about a particular live-feed strategy, not proof that every spirulina food improves growth or health.
Why this study matters
Fish-food claims often combine growth, colour and immunity. This experiment helps separate the measured outcomes and shows why the carrier, enrichment mixture and underlying diet matter when assessing an ingredient claim.
How the study worked
Participants
The study used 225 young goldfish (Carassius auratus), initially about 1.10 g, in five treatments with three replicates each. Fish were maintained in aerated aquariums in a wet laboratory for 90 days. The authors report random allocation to treatments. This was controlled freshwater tank research, not a pond or household trial.
What happened?
All groups received commercial food. Four also received live Artemia: unenriched, spirulina-enriched, canthaxanthin-enriched, or enriched with both. Artemia were enriched for 24 hours before use. This tests enrichment delivered through live feed; it does not directly test dried spirulina in finished pellets.
The comparison
Commercial food alone was the main control. Commercial food plus unenriched Artemia provided an additional comparison to help distinguish adding live feed from changing its enrichment. The combined treatment cannot attribute an effect to spirulina alone.
What was measured?
Body weight, length, survival, body composition, β-carotene, image-based colour measures, blood and immune-related markers, intestinal/liver tissue observations and selected hormone gene-expression measures. Changes in laboratory markers were not a direct disease-challenge test.
What the researchers found
| Outcome | Reported result | How to read it |
|---|---|---|
| Final weight | Combined enrichment: 5.030 ± 0.042 g; commercial-food control: 4.150 ± 0.145 g. Table 6 reports a significant difference. | The result belongs to the combination and feeding context. |
| Spirulina-only enrichment | Final weight: 4.410 ± 0.141 g; not significantly different from the control in Table 6. | Do not claim that spirulina alone increased final weight. |
| Survival and specific growth rate | Survival P=0.4239; specific growth rate P=0.0773. | Neither meets the paper’s 0.05 significance threshold. |
| Colour | Combined enrichment produced favourable image-based colour measurements and β-carotene results. | Colour findings are separate from disease resistance or lifelong health. |
Species and setting: Carassius auratus · Freshwater · Controlled aquarium/laboratory study. This entry does not establish relevance to other fish species.
Related ingredients
Spirulina ingredient profile · Artemia (brine shrimp) ingredient profile
What strengthens the evidence?
The experiment directly studied an ornamental species and included both commercial-food-only and unenriched-live-feed comparisons. It used replicate experimental units, reported random allocation, and measured growth and colour using several methods. Funding and competing-interest statements were available.
What limits the conclusions?
There were only three replicates per treatment, one life-stage population and a 90-day observation period. The combination changes several aspects of nutrition, so it cannot isolate spirulina as the cause of the strongest result. Numerous outcomes were measured; a favourable biomarker is not proof of disease prevention. The narrative describes significant differences in specific growth rate, but Table 6 gives P=0.0773, above its 0.05 threshold. We therefore do not describe that outcome as statistically significant. Raw data and supplementary analyses were not independently reanalysed. Applicability to adult pets, koi, bettas and marine fish remains untested here.
What the researchers concluded
The authors concluded that spirulina and/or canthaxanthin enrichment improved Artemia and several goldfish outcomes, with the combined enrichment producing the strongest overall profile.
Evidence.pet interpretation
The most defensible conclusion concerns the tested combined feeding strategy in young goldfish. It does not show that ordinary spirulina flakes reproduce the result, that colour intensity is a measure of overall welfare, or that live Artemia constitute a complete diet. Survival and specific growth rate did not differ significantly in Table 6. Ingredient profiles should preserve those distinctions rather than converting every favourable measurement into a general health claim.
Funding and author interests
The authors declared no competing interests. The Science, Technology & Innovation Funding Authority (STDF), with the Egyptian Knowledge Bank (EKB), provided open-access funding. Kafrelsheikh University facilities were acknowledged. Publication funding is not necessarily the same as funding all experimental costs.
Read the original research
Elshafey AE, Khalafalla MM, Abou Zaid AA, Mohamed RA, Abdel-Rahim MM. Source diversity of Artemia enrichment boosts goldfish (Carassius auratus) performance, β-carotene content, pigmentation, immune-physiological and transcriptomic responses. Scientific Reports. 2023;13:21801. doi:10.1038/s41598-023-48621-4.
Evidence.pet editorial summary · Study ID STU-016 · Source checked 23 September 2026. Strengths, limitations and interpretation are our editorial assessment, not a formal evidence grade.
Adapted from Elshafey et al. (2023), licensed under CC BY 4.0. Evidence.pet has condensed and reorganised the source and added independent editorial interpretation.
Creative Commons Attribution 4.0 licence. The source has been condensed and reorganised.