Catfish: low in mercury, low in omega-3

The one randomized trial we found that tested a catfish product used oil from the fish. It gave 29 adults over 60 with dyslipidemia 1,000 mg a day of omega-3 enriched catfish oil for 90 days, single-blind, and reported lower malondialdehyde and higher scores on the MMSE cognitive screening (p<0.05), with no effect sizes in the abstract. That is a small capsule study, and it says little about a fillet. The fillet itself is modest in omega-3. Eight USDA samples of farm-raised raw catfish averaged about 0.06 g of EPA plus DHA per 3.5 oz (100 g), and feed drives how much there is. The same samples gave 2.27 micrograms of vitamin B12 and 7.3 g of fat per 3.5 oz (100 g), ranging from 5.86 to 10.11 g. Its strong point is mercury. FDA and EPA list catfish among the Best Choices lower in mercury, and in NHANES data on 5,656 US youth, eating catfish more often showed no link with blood mercury.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Farm-raised raw catfish carried 7.3 g fat per 3.5 oz (100 g) on average, with 8 USDA samples ranging from 5.86 to 10.11 g. — Farm-raised catfish fillets, raw, 8 analytical samples (n = 8) Evidence C source
  Mean 7.308 g/100 g; range 5.86-10.11 g; spread 58%
• Farm-raised raw catfish supplied 2.27 micrograms of vitamin B12 but only about 0.06 g of EPA plus DHA per 3.5 oz (100 g) in USDA samples. — Farm-raised catfish fillets, raw, 8 analytical samples (n = 8) Evidence C source
  B12 mean 2.266 ug (1.7-2.81); DHA 0.046 g (0.027-0.086); EPA 0.015 g (0.006-0.034) per 3.5 oz (100 g)
• The UK table lists raw catfish at 2.8 g fat and 46 mg cholesterol per 3.5 oz (100 g), lower than the US farm-raised samples at 7.3 g and 66 mg. — Catfish, raw (CoFID 16-007) versus US farm-raised catfish (FDC 2684445) Evidence C source
  Fat 2.8 vs 7.3 g; cholesterol 46 vs 66 mg; iodine 90 vs 1.9 ug per 3.5 oz (100 g)

What a real portion looks like

• In US dietary survey coding, one regular fried catfish fillet weighs 3.2 oz (90 g) and one large fillet 135 g. — Fish, catfish, fried (FNDDS 26107140) Evidence C source
  Small/regular fillet 90 g; large fillet 135 g; whole fish 270 g; 1 oz yields 20 g

What cooking and storage change

• For lean fish fried with a coating, the USDA table keeps 90% of vitamin B12 and all of the minerals after cooking. — Finfish and Shellfish Products group, under 5% fat, fried with coating Evidence C source
  Retention: B12 90%, thiamin 85%, riboflavin 95%, calcium, iron, zinc, potassium 100%
• Steaming catfish flesh raised protein from 17.6 to 21.4 g per 3.5 oz (100 g) in the UK table, because water fell from 80.1 to 73.6 g. — Catfish, raw (CoFID 16-007) and flesh only, steamed (CoFID 16-008) Evidence C source
  Protein 17.6 to 21.4 g; water 80.1 to 73.6 g; energy 96 to 119 calories per 3.5 oz (100 g)

What it does to your health

• In a single-blind RCT on 29 older adults with dyslipidemia, 1,000 mg a day of omega-3 enriched catfish oil for 90 days lowered malondialdehyde and raised MMSE scores (p<0.05). — 29 adults aged over 60 with dyslipidemia, 90 days (n = 29) Evidence B source
  MDA decreased and MMSE increased, p<0.05; comparison arms and effect sizes not given in the quoted abstract text

Safety, limits and interactions

• Listeria monocytogenes was found in 25 to 47% of raw channel catfish fillets sampled from three US processing plants. — Raw channel catfish fillets from three processing plants, four time periods Evidence C source
  L. monocytogenes prevalence 25-47%
• A systematic review of 27 studies from American estuarine bays found naphthalene and pyrene routinely at high levels in catfish and white mullet. — Seafood from estuarine bays across the American continent, 27 studies (n = 27) Evidence C source
  Naphthalene and pyrene routinely detected at high concentrations; no pooled estimate

Who this works differently for

• In an RCT on 70 fish-allergic children aged 2 to 10, codfish oral immunotherapy desensitized 43% versus 11% on placebo at 52 weeks and lowered cross-reactivity to catfish allergens. — 70 children aged 2-10 with challenge-proven codfish allergy, Hong Kong, 52 weeks (n = 70) Evidence B source
  Desensitization 43% vs 11%, risk difference 32% (95% CI 9%-51%); sustained unresponsiveness 23% vs 9%, not significant
• Among 11 Thai children with IgE-mediated fish allergy, tilapia and catfish were the most common triggers. — 11 children with IgE-mediated fish allergy, Thailand, median age 3 years (n = 11) Evidence C source
  Catfish among the two most common triggers; cutaneous symptoms in 63.6%
• In NHANES 2009-2012 data on 5,656 US youth, eating catfish more often was not linked to higher blood mercury, while eating certain other seafood types more often was. — 5656 US youth aged 1-19, NHANES 2009-2012 (n = 5656) Evidence C source
  No significant association for catfish or breaded fish; certain other seafood types positively associated with blood mercury
• In a 2015 survey of 221 pregnant women in Baton Rouge, catfish was the most eaten fish but only about once a month. — 221 pregnant women, Baton Rouge, Louisiana, 2015 (n = 221) Evidence C source
  Catfish, the most consumed fish, eaten about once per month; fish eaten by 22% vs chicken 75%
• FDA and EPA list catfish as a Best Choice lower in mercury and advise 2 to 3 servings a week of such fish in pregnancy and breastfeeding. — People who are or might become pregnant, breastfeeding, and young children Evidence E source
  2-3 servings of 4 oz per week from Best Choices in pregnancy; children 1-4 oz per serving by age

The bottom line

Tables disagree on what catfish is. The UK table lists raw catfish at 2.8 g of fat and 46 mg of cholesterol per 3.5 oz (100 g), against 7.3 g and 66 mg in the US farm-raised samples. Species, farming and feed are not stated for the UK entry, so read the gap as spread between fish. A regular fried fillet is coded at 90 g and a large one at 135 g. Steaming raised protein from 17.6 to 21.4 g per 3.5 oz (100 g) in the UK table only because water fell from 80.1 to 73.6 g. For lean fish fried with a coating, the USDA factor table keeps 90% of vitamin B12 and all of the minerals, a group factor from 1975 never measured on catfish itself. For pregnancy and breastfeeding, FDA and EPA advise 2 to 3 servings of 4 oz a week from their Best Choices list, which includes catfish. Listeria monocytogenes was found in 25 to 47% of raw channel catfish fillets from three US plants, in data from 2006, so cook it through and keep raw fillets away from ready-to-eat food. A systematic review of 27 studies found naphthalene and pyrene routinely at high levels in catfish from wild American estuaries, with no human outcome measured and no data on farmed fish. Fish allergy is the caution with the most data. Among 11 Thai children with IgE-mediated fish allergy, tilapia and catfish were the most common triggers, a pattern that reflects local diet. In a randomized trial on 70 children aged 2 to 10 allergic to cod, oral immunotherapy desensitized 43% against 11% on placebo at 52 weeks (risk difference 32%, 95% CI 9% to 51%). Blood tests showed less cross-reactivity to catfish allergens, but nobody was challenged with catfish, so the trial cannot tell a parent whether a child allergic to cod can eat it.

Sources

1. ctf-daily-r4-01 · composition data
   Fish, catfish, farm raised, raw (USDA FoodData Central, Foundation Foods, release 2026-04-30): Total lipid (fat) 7.308 G, range 5.86-10.11 (median 7.125), samples 8, spread 58%
   USDA FoodData Central, Foundation Foods, release 2026-04-30, FDC 2684445 · checked 2026-09-30
2. ctf-daily-r4-02 · composition data
   Fish, catfish, farm raised, raw (USDA FoodData Central, Foundation Foods, release 2026-04-30): Vitamin B-12 2.266 UG, range 1.7-2.81, samples 8; PUFA 22:6 n-3 (DHA) 0.046 G, range 0.027-0.086, samples 8; PUFA 20:5 n-3 (EPA) 0.015 G, range 0.006-0.034, samples 8
   USDA FoodData Central, Foundation Foods, release 2026-04-30, FDC 2684445 · checked 2026-09-30
3. ctf-daily-r4-03 · composition data
   Catfish, raw (CoFID 2021, code 16-007): Fat 2.8 g; Cholesterol 46.0 mg; Iodine 90 ug per 100 g; Fish, catfish, farm raised, raw (USDA Foundation Foods 2026-04-30): Total lipid (fat) 7.308 G; Cholesterol 65.96 MG; Iodine 1.94 UG
   CoFID 2021 (Public Health England), code 16-007, Open Government Licence v3.0 · checked 2026-09-30
4. ctf-daily-r4-06 · portion data
   Fish, catfish, fried (FNDDS food code 26107140, fdc_id 2706238): 1 small/regular fillet 90 g; 1 large fillet 135 g; 1 whole fish, any size 270 g; 1 oz yields 20 g
   USDA FNDDS, FoodData Central survey foods, food code 26107140 (fdc_id 2706238) · checked 2026-09-30
5. ctf-daily-r4-04 · retention factors
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 2310 FINFISH,<5%FAT,FRIED,W/COATING: vitamin_b12_ug 90%; thiamin_mg 85%; riboflavin_mg 95%; calcium_mg 100%; iron_mg 100%; zinc_mg 100%; potassium_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 2310 · checked 2026-09-30
6. ctf-daily-r4-05 · composition data
   Catfish, raw (CoFID 2021, code 16-007): Protein 17.6 g; Water 80.1 g; Energy 96 kcal; Catfish, flesh only, steamed (code 16-008): Protein 21.4 g; Water 73.6 g; Energy 119 kcal
   CoFID 2021 (Public Health England), codes 16-007 and 16-008, Open Government Licence v3.0 · checked 2026-09-30
7. ctf-daily-r4-07 · RCT
   A total of 29 elderly subjects were chosen following these inclusion criteria: aged >60 y; had dyslipidemia; and signed the informed consent. ... The intervention was 1,000 mg oil/d administered for 90 d. ... Supplementation of catfish oil enriched with omega-3 was able to significantly decreased malondialdehyde (MDA) level (p<0.05) and significantly increased mini mental state examination (MMSE) score (p<0.05).
   J Nutr Sci Vitaminol (Tokyo), 2020 · checked 2026-09-30
8. ctf-daily-r4-10 · prevalence study
   Listeria monocytogenes was the predominant Listeria species found in these catfish fillets, with 25 to 47% prevalence.
   J Food Prot, 2006 · checked 2026-09-30
9. ctf-daily-r4-14 · systematic review (observational)
   The PICO methodology was applied, and 27 experimental papers were evaluated. The findings indicate that naphthalene and pyrene are routinely detected at high concentrations in several species, such as white mullet and catfish, and that biliary metabolites concentrations tend to be higher than tissue levels.
   Sci Total Environ, 2023 · checked 2026-09-30
10. ctf-daily-r4-08 · RCT
    At the week 52 end-of-treatment challenges, 15 (43%) OIT participants versus 4 (11%) placebo achieved desensitization (risk difference 32%, 95% CI 9%-51%; p = 0.003), with significantly greater increases in cumulative tolerated protein [median 4330 mg vs. 0 mg, p < 0.001]. ... The treatment demonstrated acceptable safety with minimal moderate-to-severe adverse events and epinephrine use (3% both groups), and immunological evidence of reduced cross-reactivity to salmon and catfish allergens.
    Allergy, 2026 · checked 2026-09-30
11. ctf-daily-r4-09 · cross-sectional
    Eleven children, with a median age of 3 years, were recruited; the median age of onset was 1.25 years. Cutaneous symptoms were the most frequent clinical manifestation (63.6%). Tilapia and catfish were the most common triggers.
    Allergol Immunopathol (Madr), 2025 · checked 2026-09-30
12. ctf-daily-r4-11 · cross-sectional
    In adjusted log-linear regression analysis, no significant associations were observed between frequency of breaded fish or catfish consumption and blood mercury concentrations, but frequency of consuming certain seafood types had significant positive association with blood mercury concentrations
    J Nutr, 2015 · checked 2026-09-30
13. ctf-daily-r4-12 · observational
    Consumption frequency for the most consumed fish (catfish, once per month) was similar to or lower than that of the least consumed beef, chicken, and pork foods.
    J Pregnancy, 2016 · checked 2026-09-30
14. ctf-daily-r4-13 · agency guidance
    Eat 2 to 3 servings a week from the "Best Choices" list (OR 1 serving from the "Good Choices" list).
    FDA/EPA Advice about Eating Fish, 2024 · checked 2026-09-30