*If you are using fish or shrimp, only let this marinade sit for 10-20 mintes. The acids in the citrus will begin to cook the proteins in the fish/shellfish, and if you leave it set longer, you will have achiote ceviche, which is arguably more lyrical, phonetically speaking, and probably delicious, just be aware of what you are doing or you will have the mushiest, mealiest, get-this-the-hell-off-my-plate-what-sort-of-sadist-are-you-to-have-served-me-this-anyway-I-thought-you-liked-me disaster that you have ever served.
**Achiote paste can be found in any Mexican market, and typically also the “ethnic” aisle of your garden-variety American megamart. Achiote is what gives cheddar cheese its searing orange color, so be careful. It stains, stains, stains.