It took a ban on booze to turn America into shrimp addicts. After the passage of the 18th Amendment shelved the country’s collective cocktail glasses, someone had the brilliant and resourceful idea to put a tangy ketchup and horseradish sauce into the stagnant stemware and drape cooked shrimp on the rim of the glass to dip. A fad—the shrimp cocktail—was born, and it remains a classic to this day.

But picking great shrimp isn’t as easy as peel-and-eat. With more than 300 species of shrimp roaming sandy waters across the planet, becoming an expert requires some key pieces of information. Here are four secrets to bring your crustacean habit to a new level.

1) Shrimp vs. Prawns. Similar in appearance and often used synonymously—and erroneously—the shrimp and the prawn are two different creatures. Both are decapod crustaceans that have 10 legs and an exoskeleton, but they fall into different suborders when it comes to scientific classification. The good thing is that you don’t need to be a marine biologist to tell them apart: In prawns, the second body chamber overlaps both the first and third, while in shrimp the second chamber only overlaps the third. Sound confusing? Don’t worry: For cooking purposes, the flavors tend to be similar. And there’s always the at-a-glance method of differentiation: Prawns tend to be larger than their shrimp cousins.

2) Not All Shrimp Are Created Equal. Different types of shrimp have different flavors. White shrimp are sweeter, which Louisiana shrimper Lance Nacio, owner of Anna Marie Seafood, attributes to the brackish waters where these shrimp are harvested. “Our shrimp are mostly sweet because they come from inshore where the waters of the Mississippi meet the waters of the Gulf.” Brown shrimp, on the other hand, retain minerals from the algae they feed on and have a stronger, more pronounced iodine flavor. Which tastes better? That’s a matter of opinion. But the secret to purchasing the freshest shrimp? The rule, says Nacio, is all in the head. “Good-quality shrimp is clear and has the smell of the sea. If the head is still intact, it means the shrimp are very fresh.” (In choosing between fresh or frozen shrimp, you should keep in mind that while fresh is best, they’ll only keep for a few days.)

3) Do You Know Your Scampi? Shrimp play a leading role in this country’s favored culinary repertoire, and shrimp scampi is one of the classics. Traditionally centered on seafood, though now most commonly using shrimp, scampi is a garlic, onion, white wine, and butter sauce made famous in Italian-American kitchens.. As an ingredient, though, scampi is actually the plural form of “scampo,” a type of Norwegian lobster, sometimes called langoustine—but not shrimp.

4) The Skinny on Shrimp and Cholesterol. Although shrimp is indeed low in fat, it’s a cholesterol killer, with a typical serving containing two-thirds of the recommended daily diet allowance. In one four-ounce serving of raw shrimp, there are 120 calories, 2 grams of fat and 172 mg of cholesterol. The same size serving of chicken contains 110 calories, 2.5 grams of fat and only 65 mg of cholesterol. Medical studies show, however, that eating shrimp may not raise your overall cholesterol level. In addition to being low-fat, shrimp is also low in sodium with one-sixth the salt content of crab. Eaten in moderation and prepared in a healthy way, shrimp can still be enjoyed by those of us watching what we eat. Just not a billion pounds of it.

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Jane Frye is an editorial assistant at The Daily Beast.