Spirulina

Spirulina in fish diets: compare goldfish live-feed enrichment with koi pigment research, and understand why ingredient presence is not proof of product performance.

Ingredient Directory›Spirulina

Ingredient & nutrient profile

Spirulina

A nutrient and pigment source whose effects depend on how it is fed and what accompanies it.

Microbial IngredientFishGoldfishKoi
SP
SpirulinaNutritional role • Research • Practical context
SpeciesGoldfish and koi evidence
ScopeIngredient and nutrient context
AssessmentInitial evidence summary
Sources checked23 September 2026
Nutritional role

What it contributes

Spirulina is a biomass ingredient used in fish feeding, including to enrich live Artemia. The linked goldfish study assessed that enrichment route. It did not directly test a retail spirulina flake or pellet.

Species and formulation

Read it in context

The linked evidence covers goldfish and koi in freshwater laboratory tanks. The goldfish study tested enrichment through live Artemia; the koi study tested spirulina in formulated experimental diets. These are different feeding strategies.

Research

What the evidence shows

In Elshafey et al. (2023), 225 young goldfish received one of five feeding treatments for 90 days. Combined spirulina/canthaxanthin enrichment produced the highest final weight and favourable colour measures. Spirulina-only enrichment did not significantly improve final weight over the commercial-food control in Table 6. The combined result cannot be credited to spirulina alone. A separate eight-week koi experiment reported better growth and redness with a spirulina diet, but used only two tanks per treatment. Neither experiment tested the retail foods linked here.

Limits and safety

Before changing the diet

Colour intensity and blood markers do not prove overall health or protection from disease. The study does not establish a household supplement dose, lifelong adequacy or benefits for every fish species. Do not assume that adding powder to an existing food reproduces controlled live-feed enrichment.

Food labels

Questions worth asking

Ask whether a claim concerns spirulina itself, an enriched live feed or a finished food containing several pigment sources. Look for named ingredients, intended species and evidence for the actual formulation. Ingredient presence alone does not establish an effective amount or a health benefit.

Connected evidence

Explore the studies

The linked study identifies the fish species, feeding method and limits of the evidence.

Koi · 2014 · Controlled feeding trialSpirulina and pigment sources in koi: an eight-week feeding studyColour and growth findings, with only two tanks per diet.Goldfish · 2023 · Controlled feeding trialEnriched Artemia for goldfish: growth and colour in a 90-day trialRead the study summary, methods and limitations.
Declared ingredient

Foods listing spirulina

Hikari Betta Bio-Gold and Hikari Excel list spirulina on their US pages. These declarations do not demonstrate the performance of either product. No betta spirulina trial is linked in this profile.

Sources

References and review scope

  1. 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.
  2. Kim YO, Lee SM. Effect of Dietary Carotenoids Sources on Growth and Skin Color of Red- and White-colored Fancy Carp Cyprinus carpio var. koi. Korean Journal of Fisheries and Aquatic Sciences. 2014;47(6):790–795. doi:10.5657/KFAS.2014.0790.

This is an initial, source-linked overview, not a systematic review or a product endorsement. Study-specific access limitations are stated above.