Safety

Mercury: the seven to limit

Most fish is low in mercury. A short list of large, long-lived predators carries the risk — and the FDA publishes exactly which ones.

The seven highest

These are literally the top seven rows of the FDA's mercury table — not a cherry-picked list. Mean mercury, parts per million.

Species	Mercury (ppm)
Tilefish (Gulf of Mexico)	1.123
Swordfish	0.995
Shark	0.979
King mackerel	0.730
Bigeye tuna	0.689
Orange roughy	0.571
Marlin	0.485

The common thread: all large, all long-lived. Mercury builds up over years, so the biggest predators carry the most.

The FDA's "Best Choices"

The full official list, verbatim — the lowest-mercury commercial species. Eat 2–3 servings a week from here. Note what's not on it: albacore ("white") tuna.

Anchovy
Atlantic croaker
Atlantic mackerel
Black sea bass
Butterfish
Catfish
Clam
Cod
Crab
Crawfish
Flounder
Haddock
Hake
Herring
Lobster
Mullet
Oyster
Pacific chub mackerel
Perch
Pickerel
Plaice
Pollock
Salmon
Sardine
Scallop
Shad
Shrimp
Skate
Smelt
Sole
Squid
Tilapia
Trout (freshwater)
Tuna, canned light
Whitefish
Whiting

How much is safe

Adults: 2–3 servings/week from Best Choices, or 1 serving/week from Good Choices. It's an either/or, not a total.
Pregnant or breastfeeding: 8–12 oz per week of lower-mercury varieties (cooked weight).
Children: 2 servings/week from Best Choices. Portion by age: 1 oz (1–3 yrs) · 2 oz (4–7) · 3 oz (8–10) · 4 oz (11+).

One honest caveat. This ranks mercury only — that's what the FDA/EPA chart measures. It says nothing about PCBs or dioxins, which failed verification for a species-by-species ranking. Some FDA mercury figures are also old (the Atlantic mackerel number is from 1978). Swordfish and shark have robust modern sampling; the "limit these" list is on solid ground.

Get the whole cheat sheet

The five swaps, the omega-3 ranking, and the label traps — one page, all sourced.

The Fish Cheat Sheet →

Mercury values — FDA, "Mercury Levels in Commercial Fish and Shellfish (1990–2012)." Species means.

Tiers and serving guidance — FDA/EPA joint "Advice About Eating Fish," rev. October 2021.

Swordfish photo: Derke Snodgrass, NOAA (public domain).