There are many delicious fast food fish sandwiches to order at drive-thrus at chains from McDonald's to Popeye's. Out of the bunch, Arby's, the fast-food chain best known for its roast beef sandwiches, also offers a solid fish sandwich to bite into. But when you order seafood from a fast-food jaunt, even one as respectable as Arby's, you might want to know what type of fish is between the buns. In this case, expect to bite into wild-caught Alaskan pollock, a relatively common variety of fish used in fried fish sandwiches.

Yes, that's right. Arby's Crispy Fish Sandwich, which rings in between $5 and $6 depending on your location, uses a crispy fish fillet made of Alaskan pollock. In fact, we've noted before that Bojangles slings a fish sandwich that likewise uses fried pollock in its version. The fish's popularity among fast food chains likely has to do with its affordability compared to other varieties. An additional perk is that the Alaskan pollock is one of the more sustainably sourced options and is also rather nutritious.

The Alaskan pollock fillet on Arby's Crispy Fish Sandwich joins shredded lettuce and tartar sauce on a toasted sesame bun. You can also order the chain's Fish 'N Cheddar Sandwich, made up of the same staples topped with a cheddar cheese sauce. Both fish sandwiches can be ordered as a meal with a side like its popular curly fries plus a drink. Additionally, it's worth noting that both fish-themed offerings are listed on the limited-time-only section of the menu, so you may not be able to indulge in Alaskan Pollock at Arby's year-round.