Mahi mahi: a lean fish in the FDA Good Choices group, with borrowed evidence

Mahi mahi counts as a lean fish by its composition, and we found no health trial that studied it by name. Everything about health here is borrowed from trials of lean fish in general. A meta-analysis of 18 to 21 randomized trials with 1392 to 1456 participants found that lean fish lowered blood triglycerides compared with no fish, while total cholesterol and lipoproteins showed no significant difference. The abstract gives no size for the triglyceride drop, and the full text was not available to us. In a separate meta-analysis of randomized trials in 640 people, lean fish did not significantly raise vitamin D (mean difference 1.9 nmol/L, 95% CI -2.3 to 6.0), while fatty fish did (6.8 nmol/L, 3.7 to 9.9). Mahi mahi itself was in none of those vitamin D studies. What the fish reliably brings is protein and selenium. Six frozen wild-caught USDA samples averaged 19.8 g protein and 50.2 mcg selenium per 3.5 oz (100 g), with selenium ranging from 42.8 to 55.3 mcg.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• In 6 USDA samples of frozen wild-caught mahi mahi, selenium averaged 50.2 mcg per 3.5 oz (100 g) (range 42.8 to 55.3) and vitamin B12 1.34 mcg (range 0.76 to 2.93). — 6 retail samples, USDA Foundation Foods (n = 6) Evidence E source
  Selenium 50.16 mcg/100 g, B12 1.343 mcg/100 g, sample ranges shown
• The same 6 USDA samples held 19.8 g protein, 408 mg potassium and 52 mg sodium per 3.5 oz (100 g), with sodium varying from 40.7 to 70.6 mg. — 6 retail samples, USDA Foundation Foods (n = 6) Evidence E source
  Protein 19.79 g, potassium 407.9 mg, sodium 51.93 mg per 3.5 oz (100 g)

What your body absorbs

• In a non-randomized trial in 71 volunteers, eating fish raised serum EPA and DHA more than cod liver oil. — 71 volunteers, 5 groups including cooked cod, 8 weeks (n = 71) Evidence C source
  Cooked salmon: EPA +129%, DHA +45% vs cod liver oil +106% and +25%

What it does to your health

• A meta-analysis of 18 to 21 randomized trials with about 1400 people found lean fish lowered blood triglycerides versus no fish but did not change total cholesterol or lipoproteins. — Adults in 24 RCTs, 18 to 21 in pooled analyses (n = 1392-1456) Evidence A source
  Triacylglycerol lowered, size not given in abstract; no change in total cholesterol
• Observational data from 5 prospective studies link the highest lean fish intake with 19% lower stroke risk (RR 0.81). — 5 prospective cohort studies Evidence C source
  RR 0.81 (95% CI 0.67 to 0.99) for lean fish

Safety, limits and interactions

• In a 2006 Lima market survey, none of 5 frozen mahi-mahi fillets from wholesale markets had histamine above 1 ppm, while raised levels were found almost only in retail-market mackerel and bonito, and 5 fillets from one city do not measure poisoning risk. — 38 fish from Lima markets: 17 bonito, 16 mackerel, 5 mahi-mahi (n = 38) Evidence C source
  0 of 5 mahi-mahi above 1 ppm
• Across 103 reported histamine poisoning incidents, the fish involved held on average 1107 mg/kg histamine, mostly tuna or marlin-family species. — 55 outbreak reports, 103 incidents, 1959 to 2013 (n = 103 incidents) Evidence D source
  Mean 1107.21 mg/kg (CI 422.62 to 2900.78)
• FDA and EPA list mahi mahi among Good Choices for mercury and advise people who are pregnant or breastfeeding to eat 8 to 12 ounces a week of lower-mercury seafood. — People who are pregnant or breastfeeding and children, US advice revised October 2021 Evidence E source
  Good Choices category

Who this works differently for

• Observational data from 35 studies link fish eating with 21% lower depression risk (RR 0.79), including depression in pregnancy (RR 0.78). — 35 observational studies, adults and pregnant women Evidence C source
  RR 0.79 (0.73 to 0.86); pregnancy-related RR 0.78 (0.69 to 0.89)
• Observational data from 31 studies link higher fish intake in pregnancy with lower food allergy in children (pooled effect 0.75) but not with asthma. — Mothers and offspring, 31 observational studies Evidence C source
  Food allergy 0.75 (0.64 to 0.88); asthma 0.99 (0.89 to 1.11)

What is still unknown

• In a meta-analysis of randomized trials, lean fish did not significantly raise vitamin D status (mean difference 1.9 nmol/L), unlike fatty fish (6.8 nmol/L). — 640 subjects, 14 study groups (n = 640) Evidence A source
  Lean fish MD 1.9 nmol/L (95% CI -2.3 to 6.0); fatty fish 6.8 nmol/L (3.7 to 9.9)

The bottom line

The composition numbers come from those 6 frozen wild-caught samples and are per 3.5 oz (100 g). Potassium averaged 408 mg and sodium 52 mg, with sodium ranging from 40.7 to 70.6 mg between samples. Vitamin B12 averaged 1.34 mcg but ran from 0.76 to 2.93 mcg, a wide spread for six fish, so treat it as rough. The dataset does not list how many samples went into the protein figure. We have no second composition source, no omega-3 figure for mahi mahi and no standard portion. Eating fish may raise omega-3 levels in the blood more than fish oil does. In a non-randomized trial in 71 volunteers over 8 weeks, eating fish raised serum EPA and DHA more than cod liver oil did. The clearest gains were in the salmon group, and mahi mahi was not studied. Observational data from 5 prospective studies link the highest lean fish intake with a lower stroke risk (RR 0.81, 95% CI 0.67 to 0.99). That interval almost touches 1, and it rests on five comparisons. Who should be careful. The FDA and EPA put mahi mahi in the group they call Good Choices for mercury. Their overall advice for people who are pregnant or breastfeeding is 8 to 12 ounces a week of a variety of lower-mercury seafood. That total covers the whole lower-mercury list, and our card does not say how much of it may be mahi mahi, so the agency's own chart is the place to check that. The safety cards also cover histamine. Across 103 reported histamine poisoning incidents in 55 outbreak reports, the fish involved held on average 1107 mg/kg histamine (confidence interval 422.62 to 2900.78), and mahi mahi was not counted separately. In a 2006 survey of Lima markets, none of 5 frozen mahi mahi fillets bought wholesale held more than 1 ppm histamine, a small sample from one city that does not measure poisoning risk. Those fillets were frozen and bought wholesale, and the survey says nothing about fish kept warm after purchase. Our cards do not cover how mahi mahi should be kept cold or whether cooking breaks histamine down, so the Lima result is not a sign that mahi mahi is safe from histamine poisoning. We have no cards on fish allergy or on drug interactions. Two more findings concern fish in general. Across 35 observational studies, eating fish was linked to a lower risk of depression (RR 0.79, 95% CI 0.73 to 0.86) and of depression in pregnancy (RR 0.78, 0.69 to 0.89). In 31 observational studies, higher fish intake in pregnancy went with less food allergy in the children (pooled effect 0.75, 0.64 to 0.88) and no change in asthma (0.99, 0.89 to 1.11). A 2026 cohort found the opposite for more than one serving a week, so the allergy signal is unsettled.

Sources

1. mahi-daily-r1-01 · dataset
   Mahi mahi, frozen, wild caught (FDC 2747658, Foundation Foods 2026-04-30): Selenium, Se 50.16 UG, range 42.8-55.3 (median 51.1), samples 6; Vitamin B-12 1.343 UG, range 0.76-2.93 (median 1.103), samples 6
   USDA FoodData Central, Foundation Foods, release 2026-04-30, FDC 2747658 (Mahi mahi, frozen, wild caught) · checked 2026-09-28
2. mahi-daily-r1-02 · dataset
   Mahi mahi, frozen, wild caught (FDC 2747658, Foundation Foods 2026-04-30): Protein 19.79375 G, range 18.0-20.625; Potassium, K 407.9 MG, range 334.0-457.0, samples 6; Sodium, Na 51.93 MG, range 40.7-70.6, samples 6
   USDA FoodData Central, Foundation Foods, release 2026-04-30, FDC 2747658 (Mahi mahi, frozen, wild caught) · checked 2026-09-28
3. mahi-daily-r1-08 · controlled trial
   In conclusion, fish consumption is more effective in increasing serum EPA and DHA than supplementing the diet with fish oil.
   Lipids, 2006 · checked 2026-09-28
4. mahi-daily-r1-05 · meta-analysis of RCTs
   Meta-analysis of data from 18 to 21 eligible crossover and parallel-design RCTs with a total of 1392 to 1456 participants found triacylglycerol-lowering effects for lean fish compared with no fish consumption. Lean fish intake showed no significant differences related to total cholesterol or lipoprotein levels.
   Nutr Rev, 2021 · checked 2026-09-28
5. mahi-daily-r1-07 · meta-analysis of cohorts
   Compared with the highest category of intake with lowest category, the summary relative risk was 0.88 [95% confidence interval (CI), 0.74-1.04] for fatty fish intake and 0.81 (95% CI, 0.67-0.99) for lean fish intake.
   Lipids Health Dis, 2018 · checked 2026-09-28
6. mahi-daily-r1-03 · prevalence survey
   All five mahi-mahi, four mackerel, and four bonito were purchased from WFMs. ... All 10 specimens with >1 ppm were from RFMs, except for 1 mackerel with 2.8 ppm that was from a WFM (Table 2).
   J Food Prot, 2009 · checked 2026-09-28
7. mahi-daily-r1-04 · meta-analysis of outbreak reports
   Fifty-five (55) reports were included, these studies reported 103 incidents. All pooled analyses were based on random effect model; histamine mean concentration in poisoning samples was 1107.21 mg/kg with confidence interval for the meta-mean of 422.62-2900.78 mg/kg
   Crit Rev Food Sci Nutr, 2018 · checked 2026-09-28
8. mahi-daily-r1-11 · agency advice
   Mahi mahi/dolphinfish ... Those who are pregnant or breastfeeding consume between 8 and 12 ounces per week of a variety of seafood from choices that are lower in mercury.
   FDA and EPA, Advice about Eating Fish, revised October 2021 · checked 2026-09-28
9. mahi-daily-r1-09 · meta-analysis of observational studies
   A significant inverse association was found between fish consumption and depression risk (RR = 0.79, 95% CI: 0.73 to 0.86). A similar association was observed for pregnancy-related depression (RR = 0.78, 95% CI: 0.69-0.89).
   Nutrients, 2025 · checked 2026-09-28
10. mahi-daily-r1-10 · meta-analysis of observational studies
    Greater maternal fish intake was associated with a reduced risk of wheeze (Pooled effect size: 0.97; 95% CI: 0.96-0.99) and food allergy (0.75; 95% CI: 0.64-0.88). Maternal fish consumption was not associated with risk of asthma (pooled effect size: 0.99; 95% CI: 0.89, 1.11)
    Crit Rev Food Sci Nutr, 2022 · checked 2026-09-28
11. mahi-daily-r1-06 · meta-analysis of RCTs
    The type of the fish also played a key role: the consumption of fatty fish resulted in a mean difference of 6.8 nmol/L (95% CI: 3.7, 9.9 nmol/L; P < 0.0001, I(2) = 0%; 7 study groups), whereas for lean fish the mean difference was 1.9 nmol/L (95% CI: -2.3, 6.0 nmol/L; P < 0.38, I(2) = 37%; 7 study groups).
    Am J Clin Nutr, 2015 · checked 2026-09-28