Rainbow trout

Rainbow trout is notable for histamine. Clear on FODMAPs, lactose, gluten, fructose, oligosaccharides, sorbitol, sucrose, tyramine, salicylate, nickel and oxalates.

Rainbow trout contains only low levels of histamine. Rainbow trout is farmed, killed to order and often sold within a day - the cold chain is short by design because the fish never travels far. Low free histidine, like all the lean freshwater fish. What changes the answer is smoking, which is a different entry entirely. Krizek stored carp, rainbow trout and perch at 3 °C and at 15 °C: fillets kept 11 to 16 days and mince 7 to 10 at the low temperature, against 2 to 3 days at the high one — and samples still of good or acceptable quality carried no toxicologically significant histamine or tyramine at all. Putrescine, not histamine, was the amine that tracked spoilage. The legal 100 and 200 mg/kg limits are written for the histidine-rich scombroids, not for this fish — which does not exempt it from the clock. Amounts vary by brand and recipe, so always check the label of the exact product.