14 Underrated Toppings To Add To Your Fish Sandwiches

The most satisfying fish sandwich dishes out a crispy-fried crunch with a chewy bread and a tender, flaky fillet. But if you've been searching for a show-stopping topping to knock this comfort food classic out of the park, welcome to the official headquarters of all the sauces, dips, and spreads you totally forgot about. (Ketchup, amiright?)

Americans chow down on about 300 million McDonald's Filet-O-Fish sandwiches per year — a stark contrast to the 1960s when the first fish sandwich won out over a pineapple-and-cheese Hula Burger to wow the Mickey D's customers who skipped meat on Fridays. (Filet-O-Fish beat the Hula Burger 58 to 1 in sales.) So now that fans have professed their undying devotion to this sea-worthy sammie, what topping goes best with a fish sandwich? You could go traditional with melted cheese, or load up on obligatory dill pickles, but you still might find yourself searching for a fish sandwich topping other than the typical tartar sauce.

Once you've nailed the best fish to use for a fried fish sandwich and the absolute best (and worst!) way to bread a fish sandwich, it's all about the fine art of accouterment. Turn your catch of the day into the catch of the yay. These 14 underrated fish sandwich toppings drop it like it's hot, cool, tangy, citrusy, and sensationally sweet.

Harissa: It's not just for spaghetti anymore! This hot Tunisian paste crafted with dried chiles, garlic, salt, and spices makes for a smoky, earthy, and slightly sweet fish sandwich spread straight out of the jar. But stir it into a little mayonnaise and you'll want to drizzle it on everything times infinity.

This multi-cultural North African condiment has fully entered the zeitgeist in the U.S. with even brands like Heinz introducing a squeeze bottle roasted red pepper harissa aioli in 2024. It's become such a staple for its versatility. While peppers lend harissa its signature heat, and spices like coriander and cumin give it warmth, the addition of mayo levels up the acids in the flavor profile, which cuts against the richness of a fried tilapia fillet. Don't stop there with the harissa, though. Beyond acting as a dressing, the fish-friendly dry seasoning version of harissa can also tag in as a spice rub. You can even add harissa seasoning to the batter for frying your fish sandwich. Call our 24/7 hotline if you discover anything that harissa can't do.

Basic? Maybe. Sweet and totally tomatolicious? Heck yeah. Way less watery than fresh tomatoes, ketchup lands a knockout punch by stealthily serving up taste bud-tingling acids with a sprinkle of sugar for your fried fish fillet.

Ever since breaded fish sticks rolled off the Birds Eye factory line in the 1950s, people have been drowning them in ketchup. (The hashtag "fish sticks with ketchup" reportedly has over 143 million posts on TikTok, mkay?) Take another lil hint from the iconic British fish fingers sandwich which has lifelong fans tapping the vinegary tomato sauce as one of its best-loved toppings. (Giant asterisk: Yes or no on the ketchup depends greatly on who you ask. When one r/AskUK Reddit user slandered someone else's ketchup as "a children's condiment," another quickly fired back, "Yeah, like a fish finger sandwich is the height of adult sophistication.") As a stand-alone option, coupled with mayo, or sandwiched between two slices of bread with butter, tartar sauce, pickles, onion, and watercress, ketchup just might offer the one thing no other ingredient could ever so brilliantly elicit: nostalgia. Okay, pass the bottle — gotta gently tap the 57, shake it upside down, and chant "fish sticks" three times to get the ketchup to come out.

For a tangy, creamy sauce with a bit of French flavor, ditch a snoozy side of tartar sauce for something more sophisticated. Pinkies out — subbing in a rich, pickled, and herby remoulade is the golden ticket to a subtly sublime fish sando.

While traditional remoulade looks a lot like its tartar sauce cousin, it gets its perfectly bougie name from the local word for horseradish (rémolat) in the town of Picardy, France, where it was born. Now often made without the addition of peppery horseradish, it's the briny flavor of the capers, pickles, and occasional anchovies — always heavy on the fresh, aromatic herbs — that makes this rich, mayonnaise-based dressing an easy way to fancy up your fish (and it's even more convenient if you buy it pre-made). Top a Cajun fried catfish po' boy, or a grilled white fish sandwich, or break with tradition entirely and add a little hot sauce for a kicky remoulade that'll spice up a fish or crustaceous crab cake sandwich lickety-split.

Nut butter lovers, unite. Peanut butter-adjacent tahini spread emerges as the fish sandwich soulmate you've been looking for your whole life — only to realize it was right there in front of you the whole time. This roasted sesame seed paste gets a flavor-packed remix as it's blended into the garlicky, lemony topping your fish sando's been asking for.

With roots going back to India in 5000 B.C., sesame seeds are currently in their Ethiopian era (that's where some of the best seeds come from these days) but maintain their cultural import worldwide. Tahini spread or dip (many people just call it tahini) blends sesame seed paste with lemon juice, cumin, and salt to form a smooth, tangy, acidic dressing that adds a little fiber and healthy fat to go with the regularly scheduled delightfully greasy fried-ness. Try mixing standard sesame seed tahini paste into yogurt for a bun-worthy spread, or toss tahini dip into a simple cabbage slaw for a crunchy, tangy topping you could eat all by itself.

Dynamo Korean pantry staple gochujang comes as a deep red, fermented paste made of chili pepper flakes, sticky rice, soybeans, and salt (you've probably seen it in kimchi). It's sweet, spicy, and ultra umami — with just enough heat to satisfy the thrill-seekers while also bringing maximal flavor. While gochujang fulfills standard hot sauce duty as a complement to just about any food, it's a natural fit for your next fish sammy, a.k.a. gochu-sando-jang.

Take a page out of the fried chicken sandwich playbook and sub in a breaded fish fillet where the chicken would usually be. Then, layer herbed mayo, lettuce, and pickles inside a marshmallowy potato bun with gochujang, lending the heat to those creamy, briny flavors. You can also mix a little gochujang into a traditional tartar sauce recipe to add more depth of flavor. But Sriracha fans, you are not forgotten. While it's a toss-up as to which cult-favorite sauce comes out on top in a gochujang vs. Sriracha showdown, Eastern Thailand-original Sriracha serves a similar function to the Korean condiment, while leaning on a milder, sweeter, garlicky-er flavor profile. If you want umami, tang, and earthy spice, these two toppers are a win-win.

Chimichurri dishes up the "Oh ... duh" moment for fish sandwich toppings. Why wouldn't this fragrant, oily, herby green sauce taste great on a flaky white fish fillet?

Maybe more commonly found drizzled over a flank steak, spooned over grilled halibut fish tacos, or spread across a crusty baguette, Argentinian and Uruguayan-born chimichurri packs practically all of the herbs in your garden (give or take a few leaves) into one versatile sauce. While rough-chopped parsley and oregano lead the charge — along with olive oil, vinegar, crushed red pepper, and garlic — in a traditional chimichurri dressing, this condiment gets zhuzhed up as a bona fide sauce with the addition of parsley and jalapeños in a blender. Commonly served room-temp or even chilled, both chimichurri varieties offer plenty of fresh, almost grass-like, peppery flavor to contrast the fried batter or rich dairy of a typical fish sandwich. As far as any bits of parsley stuck in your teeth, however, we'll just have to let you take it from here.

Top things off with the flavors of Catalonia, Spain by adding a spoonful of romesco sauce to your fish sandwich routine. This roasted nut-filled, smoky tomato paste can be enjoyed warm, chilled, thick, thin, super spicy, or mild — and all the things in between.

Once used to upgrade a run-of-the-mill fisherman's catch in the 1700s, contemporary tomato sauce aficionados know that romesco sauce goes with everything from meat, to eggs, to potatoes, and toast. Ingredients like hearty Brandywine tomatoes, toasted almonds, garlic, red pepper, and chili create a warm, earthiness for a fried fish fillet, while brightening the scene thanks to the naturally occurring citric acids in the tomatoes. Throw the expected cod fillet out the window and cook up a mackerel fish sandwich with a romesco spread. This tuna-like fish will be singing a duet paired with a fruity, smoky, robust romesco spread on a toasted bun.

This smoky alternative goes out to all the ketchup haters out there. While barbecue sauce fans might be the first to claim that this stuff goes with anything, it's a surprisingly adaptable condiment that offers a little something for everyone's fish sandwich.

Barbecue sauce can function as a marinade, a glaze, a last-minute topping, or a slaw-based dressing — but what it does best is add unfussy, earthy, smoky flavor in a snap. Try a sweet and tangy barbecue sauce with a fried perch fillet, a bacon-like hickory barbecue sauce glaze on a grilled salmon sandwich, or break out your favorite barbecue sauce to top a tilapia sandwich, along with peppery arugula and all the melted cheddar cheese. Barbecue sauce might best serve a battered and fried fish sandwich, and could overwhelm a more mild-tasting white fish fillet. But, then again, when you love barbecue sauce, that's kind of what you're going for.

If you've got a hankering for the world's most decadent sandwich, grab the nearest fish fillet because we're leveling up the sauce situation with hollandaise. Yeah, it's the creamy stuff from a perfect eggs Benedict. (Why didn't we think of this already?)

With all due respect to one of the five mother sauces of classic French cuisine, you can buy this semi-intimidating sauce ready-made in a jar. (You can also make a mock hollandaise with mayo if you're short on time.) But no matter whether you grab it to go or cook it up yourself, hollandaise doesn't play like other sauces, all nerding out by brightening the palate with contrasting flavors. Instead, it's here to pile onto the already-rich fish sandwich with every supremely velvety, saucy bite. True hollandaise involves whisked butter, egg yolks, and lemon juice cooked low and slow to achieve an other-worldly fluffiness, especially for a cream sauce. (Ugh, fine, we'll admit that the lemon does do some tangy, contrasty flavor stuff.) Regardless, you'll be pulling out all the stops in pairing creamy hollandaise with the crunch of a beer-battered fried catfish sando. You may never think of tartar sauce ever again.

Representing the comforting final touch for the skewered meats of 8th century Indonesia, modern-day satay sauce steps into the role of OMG I Bet This Tastes Amazing on a Fish Sandwich — and you better believe it does. While there are several varieties of satay sauce, we're all in on the one with the peanuts.

Serving as a traditional hawker-style companion to marinated and grilled chicken, pork, beef, or goat, satay sauce shines just as bright once you swap out the chicken for the chicken of the sea. A coconut milk base plays host to a smooth blend of roasted peanuts, chiles, vinegar, shrimp paste, and sugar, offering a velvety texture with a definite kick. While recipes vary based on the region of the world and might include soy sauce and red curry paste, or lemongrass, garlic, and ginger-like galangal, the effect on a fried fish sandwich remains the same: a zingy pop that brings any type of fish to life (luckily, not literally). Add some crunch with a quick kimchi slaw and never go back to drive-thru Filet-O-Fish again.

By this point, we've firmly established our committed relationship with thick, creamy sauces on fish sandwiches. But while we're riffing on the underrated toppings du jour, let us never overlook the tangy, stays-out-late-and-drives-a-Camaro older sister of regular mayonnaise: sour cream. She's edgy, she's smooth, and she's a shoo-in for a fish sandwich.

Buy it at the store or whip up your own sour cream at home, this is one easy way to totally transform your fish sandwich. Spread it straight, no chaser, or mix it up with fresh dill and chopped garlic for a topping that elevates a blackened cod fillet into a Michelin-star dish. Switch up the herbs by adding fresh cilantro and lime or sub in a powerhouse seasoning like adobo, Old Bay, or your favorite hot sauce. With possibilities ranging from chip dip vibes to upscale restaurant-energy Worcestershire sauce with a sprig of decorative parsley, this is sour cream's world and we're all just eating fish sandos in it.

If you haven't heard of Nashville hot chicken by now, you might be living under a lightly seasoned rock. The story of this spicy bird leads back to 1930s Tennessee and a hot-as-hell fried chicken recipe created by Thornton Prince's angry girlfriend who sought revenge via extra hot peppers. But we're ditching everything but the side of hot honey that often comes with this dish and, instead, we humbly suggest drizzling it on your fish.

While you can stay on theme by breading your fish fillet in something akin to a Nashville-style batter, it's the hot honey element that adds the perfect amount of sweet, sticky heat. Hot honey may have its roots in the old Italian tradition of introducing pepperoncini into honey, but its current buzz (ever heard of it on pizza?) keeps the fire burning. You can buy it, but you could also infuse your own honey jar with dried chili peppers or even habanero peppers — depending on exactly how scorching you like your heat. Hot honey is so good on fried fish for the same reason it works gangbusters on fried chicken; sweet complements salty and viscosity contrasts crunch. Now, all you have to do is find the perfect potato bun to harness the heat of this winning combination.

Sticking with the sweet stuff, tap into a favorite Turkish treat by drizzling your fish sandwich in a tart pomegranate and syrupy molasses topping. What started as a street food in Istanbul can now star as your signature fish sandwich any day of the week.

Also called balik ekmek, a traditional version of this sandwich always includes grilled mackerel — which often has a stronger, fishier, more oily flavor than the typical fried white fish fillet — which is then topped off with a bit of crunchy veg and fresh mint to lighten up the pungent fish, all tossed into the dressing. Made of olive oil, lemon juice, pomegranate molasses, mild and flavorful Aleppo-style pepper, tangy sumac seasoning, and garlic, the sweet and tart flavors of the dressing instantly transport you to sunset at the Bosphorus Strait, where street vendors cook up your favorite sandwich for you — and all you have to do is eat it.

We're not saying you have to run out to get the $80+ yuzu caviar fish sandwich from Daybird LA, but we're not telling you not to do that, either. The most expensive sandwich on the Los Angeles restaurant's menu did indeed feature a dolled-up hot and crispy fried cod sandwich with a slice of cheese and a yuzu juice and yuzu kosho-powered tartar sauce dotted with actual caviar. (Opt in on the 30 grams of caviar for an additional $80.)

Considered to be a native of China or Korea, yuzu fruit also cozied up with Japanese cooking, which helped popularize the ingredient in the U.S. Looking like lemons on the tree and tasting like a grapefruit, an orange, and a lemon had a baby, its lip-puckering flavor mellows out when combined with yogurt or mayonnaise. A bright relish-like yuzu kosho would also morph into a fish sandwich topper when buckled into a velvety vehicle like a cream sauce, and slathered on a warm, toasted bun. If you love the sour notes of this citrusy, floral fruit, you won't be mad about tasting it on your next fish sandwich.