Research & Insights
Brewer's Yeast in Ornamental Fish Food: Flakes, Pellets and What the Research Shows
Published
Brewer's yeast is a protein and flavour ingredient in aquarium flakes, pellets and pond sticks. In a 2016 goldfish trial, replacing 35% of the fish meal protein with brewer's yeast gave the best growth and feed conversion of five diets, with no change in survival. For importers, aquarium food sits under pet food rules in the EU and UK.
This guide is for ornamental fish food brands, contract manufacturers and the importers who supply them. It covers why formulators use brewer's yeast, what the published trial measured, how protein needs vary between common species, and what to agree with a supplier.
Why do fish food makers use brewer's yeast?
Ornamental fish food is a small-batch, high-value product, and formulators want ingredients that bring protein without the price swings of fish meal. Dehydrated brewer's yeast averages 48.9% crude protein on a dry matter basis across 108 samples in the Feedipedia database, with lysine at 6.3% of the protein and phosphorus at 13.1 g per kg of dry matter.
It also suits the way flakes and pellets are made. Flake lines start from a fine slurry that is spread and dried on a heated roller, and extruded or pressed pellets start from a fine dry mix. A free-flowing, low-moisture powder blends into both without extra grinding at the customer's plant.
What did the goldfish feeding trial show?
Gümüş, Aydin and Kanyilmaz published the clearest dose study for an ornamental species in the Iranian Journal of Fisheries Sciences in 2016. They fed juvenile goldfish (Carassius auratus) five diets with the same protein and energy, and changed only how much fish meal protein was replaced by brewer's yeast.
| Trial detail | Value |
|---|---|
| Species and start weight | Goldfish, 0.56 g average |
| Diets | 37% crude protein, 3,350 kcal/kg, all five diets |
| Fish meal protein replaced by brewer's yeast | 0, 15, 25, 35 and 45% |
| Duration and setup | 84 days; three tanks of 20 fish per diet in 65 L aquaria |
| Best weight gain, SGR, FCR and protein efficiency | 35% replacement |
| Optimum from regression on growth rate | 34.875% replacement (R² = 0.9977) |
| Survival, liver index, body composition | No significant difference between diets |
The useful number for a formulator is the optimum near 35%. It means a goldfish recipe can move about a third of its fish meal protein to brewer's yeast and still grow fish at least as well as the all-fish-meal control.
How much protein do common aquarium species need?
Protein needs in ornamental fish vary widely, so a single protein source rarely carries a whole recipe. Velasco-Santamaría and Corredor-Santamaría collected published requirements for freshwater ornamental species in a 2011 review in Revista MVZ Córdoba.
| Species | Dietary protein requirement |
|---|---|
| Discus (Symphysodon aequifasciata) | 44.9 to 50.1% |
| Goldfish, larvae | 53% |
| Goldfish, juveniles | 29% |
| Tinfoil barb (Barbodes altus) | 41.7% |
| Guppy (Poecilia reticulata) | 30 to 40% |
| Swordtail (Xiphophorus helleri) | 30 to 45% |
| Angelfish (Pterophyllum scalare) | 26% |
| Dwarf gourami (Colisa lalia) | 25% |
With 40 to 46% crude protein as shipped, dried brewer's yeast already sits at or above the requirement of most species on this list. That gives a formulator room to use it as a main protein carrier in community and goldfish foods, and as a partial replacement in high-protein discus or fry diets.
Is aquarium fish food regulated as pet food?
In the EU and the UK, yes. Regulation (EC) No 767/2009 defines a pet animal as any non-food producing animal of a species fed, bred or kept but not normally used for human consumption. Aquarium and pond fish fit that definition, so their food is pet food under feed law, with the same labelling rules.
The yeast itself is feed material 12.1.5, "Yeasts [brewers' yeast]", in the EU Catalogue of feed materials (Regulation (EU) No 68/2013), which the UK has retained. The catalogue lists it under fermentation products that are inactivated, with no viable micro-organisms in the feed material. Moisture and crude protein are compulsory declarations when moisture is below 75%.
In the United States, the ingredient name is "brewers dried yeast": dried, non-fermentative, non-extracted Saccharomyces yeast from brewing beer and ale, with at least 35.0% crude protein, as set out in California Code of Regulations Title 3, §2801.
What should a fish food maker ask the supplier?
| Specification line | TBESBY dried brewer's yeast |
|---|---|
| Crude protein | 40 to 46% |
| Moisture | below 10% |
| Ash | below 6% |
| Crude fat | 0.5% maximum |
| Crude fibre | 1.5% maximum |
| Lysine | 30.5 g per kg |
| Shelf life | 12 months |
| Packing | 25 kg bags; jumbo bags of 600 to 1,200 kg |
| Facility and system | U.S. FDA registered facility; ISO 22000:2018 |
Add the lines that matter for your own line: particle size for flake slurry or pellet press, microbiology limits, and any contaminant limits your markets require. Ask for a certificate of analysis with each shipment, and confirm the yeast is inactivated so the EU or UK importer can declare it under entry 12.1.5.
We make TBESBY from fresh brewer's yeast supplied by leading international breweries in Vietnam, drum-dried at our own facilities in Vietnam, then milled, sieved, packed and tested. Small fish food brands usually start with 25 kg bags; contract manufacturers running several lines often move to jumbo bags.
To compare options, see our brewer's yeast for aquafeed page and the product specifications, or contact us for the spec sheet. For food fish, read brewer's yeast in tilapia feed and our aquaculture guide.
Sources
- Gümüş, E., Aydin, B. and Kanyilmaz, M. (2016). Growth and feed utilization of goldfish (Carassius auratus) fed graded levels of brewers yeast. Iranian Journal of Fisheries Sciences 15(3): 1124-1133
- Velasco-Santamaría, Y. and Corredor-Santamaría, W. (2011). Nutritional requirements of freshwater ornamental fish: a review. Revista MVZ Córdoba 16(2): 2458-2469
- Feedipedia: Brewers yeast datasheet (INRAE, CIRAD, AFZ, FAO)
- Regulation (EC) No 767/2009, Article 3: Definitions
- Regulation (EU) No 68/2013, Catalogue of feed materials, Part C, chapter 12
- California Code of Regulations, Title 3, §2801: Yeast Products
Frequently asked questions
How much brewer's yeast can go into goldfish food?
In a 2016 trial, replacing up to 35% of fish meal protein with brewer's yeast gave the best growth and feed conversion, and regression put the optimum at 34.875%. Survival did not differ between diets.
Is brewer's yeast used in fish flakes?
Yes. It is a fine, low-moisture protein powder that blends into the slurry used for flakes and the dry mix used for pellets and sticks.
Is aquarium fish food pet food in the EU?
Yes. Regulation (EC) No 767/2009 defines pet animals as non-food producing animals not normally used for human consumption, which covers aquarium and pond fish. Their food follows pet food labelling rules.
What protein level do ornamental fish need?
It depends on species and life stage, from about 25% for dwarf gourami to around 50% for discus and 53% for goldfish larvae, according to a 2011 review of published requirements.