Why salmon is orange, and what the colour can’t tell you

Nothing is injected

A common myth says farmed salmon is dyed or injected. It isn’t. The colour is astaxanthin, a red pigment salmon can’t make themselves. Wild salmon get it from the small crustaceans they eat. Farmed salmon get it in their feed. Without it, farmed salmon flesh would be pale.

A colour scale numbered 20 to 34

The salmon trade talks about fillet colour in numbers. The usual reference is the SalmoFan™ from the feed-additive company dsm-firmenich, a fan of colour cards numbered 20, the palest, to 34, the deepest. Farms aim for a shade, and buyers specify one.

This number measures colour. It doesn’t say where the pigment came from, or whether the fish was wild or farmed.

How much goes in the feed

• 100 mg/kg EU limit for astaxanthin in fish feed
• 80 mg/kg US limit for astaxanthin in salmon feed
• 10–18% of feed cost, by estimate

How much pigment goes into feed is regulated. In the EU, fish feed can hold at most 100 mg of astaxanthin per kg, and no more than 100 mg/kg when it is mixed with other pigments of its kind. In the US the limit for salmon feed is 80 mg/kg. Pigment is also one of the expensive parts of the feed: estimates run from about 10% to 18% of a farm’s feed cost.

The EU authorisation dates from 2015 and is up for renewal. The EU food safety agency EFSA published its opinion in April 2026.

What does tell wild from farmed

1. The label

In the EU, fresh, frozen, smoked and salted fish must be labelled with the species, its scientific name, whether it was caught or farmed, and where. In US shops, fish must say whether it is wild or farm-raised, though restaurants, sushi, smoked and canned salmon are exempt. US salmon fed astaxanthin must also declare it, with wording such as “color added” or “artificial color added”.

2. A lab test

Synthetic astaxanthin is a 1:2:1 mix of three mirror-image forms of the molecule. The pigment wild salmon get from their food is mostly one of them. A lab can measure that mix and tell the two apart, which is one way to check a fish sold as wild.

When the label is wrong

A label is only as good as the seller. DNA studies keep finding salmon sold as something it isn’t.

• United States, 2013–14: 43% of 82 salmon samples from shops and restaurants were mislabelled. Most of those were farmed Atlantic salmon sold as wild. (Oceana, 2015)
• Seattle sushi restaurants: 10 of 31 fish sold as wild salmon were farmed Atlantic. In Seattle grocery stores, none of the fish sold as wild were farmed. (PLOS One, 2024)
• Chile, ten cities: 19 of 84 sushi rolls sold as salmon were rainbow trout, which gets its colour from the same pigment. (Foods, 2020)

So the colour tells you how much pigment ended up in the fish. Whether the fish was wild or farmed is on the label, and only a lab can check that the label is right.

Sources

• ASC, How does salmon get its colour? (2022)
• Nofima, Pigmentation in salmon
• dsm-firmenich, Digital SalmoFan™
• Commission Implementing Regulation (EU) 2015/1415 (astaxanthin in fish feed)
• US 21 CFR 73.35 (astaxanthin) and 101.22(k)(2) (colour labelling)
• Regulation (EU) 1379/2013, Article 35 (consumer information)
• US country-of-origin labelling, 7 CFR Part 60
• Moretti et al. 2006, Food Additives & Contaminants (synthetic 1:2:1 mix)
• Rüfer et al. 2008, British Journal of Nutrition (wild vs farmed isomers)
• Turujman et al. 1997, J AOAC International (telling wild from farmed)
• Baker et al. 2002, Animal Feed Science and Technology (pigment 10–15% of feed cost)

SalmoFan™ is a trademark of dsm-firmenich, named here only to identify it. The swatches on the live page are our own.

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