Let's Chat About Mahi‑Mahi & Watermelon Ceviche
Alright, so you know those days when it’s so hot you start contemplating dinner straight form the fridge? That’s how I first ended up making this mahi-mahi & watermelon ceviche. I blame my cousin Dave, who once showed up at a cookout with a truckload of watermelon and a fish fillet he swore was “the freshest catch this side of the bridge.” (He was mostly right, except he left the fillet on the dashboard for a bit…but that’s another story.)
Anyway, this ceviche sort of became my secret weapon for impressing people with almost no effort. And I love how the watermelon’s sweetness plays with the tangy lime and tender fish. Plus, it looks gorgeous—like something you’d pay way too much for at a fancy beach bar, except you made it at home, probably in your pajamas.
Why You'll Keep Coming Back to This
I make this when my fridge is looking sparse but I’ve got a decent chunk of watermelon and some fish lying about. My niece thinks it’s "fancy salad," but my brother mostly just likes that he doesn’t have to wait for the oven to heat up. (And sometimes I make it just to prove I can chop things smaller than my pinky nail, which is way harder than it looks.)
Oh! And for anyone who hates turning on the stove during July—this is your jam. I did once try to shortcut the citrus marinating time, and let’s just say: don’t. The fish will taste more like, well, raw fish. Lesson learned (so you don’t have to repeat my mistake).
Here’s What You’ll Need (Substitutions & All)
- 250g (or about half a pound) fresh mahi-mahi, cut into ½-inch cubes (If I can’t find mahi-mahi, I’ve swapped in snapper, or even tilapia in a pinch—no one complained!)
- 1 generous cup seedless watermelon, diced (Cantaloupe works too. Granny always used melon balls, if you’re feeling retro)
- ¼ red onion, finely chopped (White onion is fine, but red looks so pretty)
- Juice of 4-5 limes (or lemons if that’s all you have; I’ve done both—works!)
- 1 jalapeño, seeded and diced (Or serrano if you want more heat, or skip it if you’re not into spice)
- A handful of fresh cilantro, roughly chopped (I know some folks think it tastes like soap—parsley is okay instead)
- Sea salt, to taste (Table salt works, pink salt if you’re feeling fancy)
- 1 small cucumber, diced (Optional, but I love the crunch)
- Drizzle of olive oil (I’ve forgotten this before, still tasty, but it adds a little something)
How I Throw This Together (With a Few Little Sidetracks)
- Chop the Fish: Cut your mahi-mahi into little cubes, about the size of dice. (This is where I usually realize my knife could use a sharpening. Oh well.)
- Marinate: Toss the fish in a glass bowl (or plastic, if that’s all you’ve got—just don’t use metal, trust me), and pour over the lime juice. The fish should be fully submerged—if not, squeeze another lime or two. Pop it in the fridge for at least 30 minutes, but I usually let it go an hour. This is the perfect window to clean up or call your mum, if you’re anything like me.
- Mix the Rest: In another bowl, throw together the watermelon, onion, jalapeño, cucumber (if you’re using), and cilantro. Add a pinch of salt. Take a quick taste—try not to just eat this as-is, but I won’t judge.
- Combine: Once your fish is opaque and ‘cooked’ by the lime (don’t worry if it looks kinda weird at first—it sorts itself out), drain off most of the citrus juice. Mix in the watermelon mixture and drizzle a bit of olive oil.
- Final Seasoning: Add more salt if you need. Maybe a bit of pepper, or even a dash of hot sauce if you’re wild. Stir, then let it sit for another 10 minutes in the fridge (or as long as you can stand—sometimes I just dig in right away).
Things I’ve Learned (Some the Hard Way!)
- If you forget the fish in the lime for hours, it gets a little tough. Still edible, but not as good. Set a timer—you’ll thank me.
- I used to skip draining off the citrus, but it ends up kinda soupy. Now, I just drain most of it and keep a little for flavor.
- Don’t go overboard with the onion. I did that once and, wow, it was pungent enough to clear a room.
Variations I’ve Actually Tried (Plus One Dud)
- Mango instead of watermelon: Super tasty, but a bit sweeter. Nice for a switch-up.
- Add avocado: Creamy and pretty, but slice it right before serving or it starts looking sad.
- Once tried canned fish: Yeah, don’t. It wasn’t the same at all, kind of mushy—I chalk that up to the learning curve.
If You Don’t Have All the Equipment...
Honestly, a sharp-ish knife and a couple bowls are really all you need. I once used a mug (don’t ask) to squeeze limes when I couldn’t find my juicer. Worked a treat, actually.
How Long Will It Last? (Spoiler: Not Long at My Place)
This ceviche is best fresh, but it’ll keep in the fridge, covered, for a day—maybe two if you’re lucky. But, to be honest, mine rarely makes it past dinner. Something about the bright flavors just makes it disappear. If you're into food safety, you can read more about fish storage here (I actually refer to this more often than I care to admit).
How I Like to Serve It (And My Family's Odd Tradition)
I love piling this onto crispy tortilla chips, but my uncle insists on saltines (I don't get it either, but hey, family). Sometimes we pile it into lettuce cups if we’re feeling "healthy." On a hot day, it even works as a taco filling with a sprinkle of feta (don’t knock it till you try it).
Pro Tips I Only Learned After Messing Up
- I once tried rushing the marinating—bad idea. The fish wasn’t cooked through and it just tasted weird. So yeah, patience pays off here.
- Bonus: If you chill your serving bowls first, the ceviche stays cold longer. Not essential, but nice if you’re eating outside. Saw this on Bon Appetit and thought, why not?
Your Actual Questions (And My Real Answers)
- Can I use frozen fish?
- Sure, if it’s super fresh-frozen and you thaw it properly. Sometimes I do! Just check out directions for safe seafood thawing here.
- Is it safe to eat raw fish like this?
- The citrus 'cooks' the fish, but if you’re worried, buy sushi-grade. Or, honestly, just make a veggie version and skip the fish—still yum.
- What can I do if I hate cilantro?
- Swap in parsley, or even basil for a different twist. Or skip it. Don’t sweat the small stuff.
- I don’t like spicy—do I have to add the jalapeño?
- Nope. Just leave it out or go easy. (No one’s judging. Promise.)
- Can I make this ahead?
- Yes, but like I said, I think it’s best just after the fish’s cooked in citrus, when everything’s still crisp. Next-day works, but the watermelon releases more juice (sometimes I just eat it with a spoon at that point, call it ceviche soup).
And just as a side note—every time I make this, there’s some new little twist I stumble on. Sometimes for better, sometimes... not so much. But I guess that’s half the fun of cooking, right?
Ingredients
- ½ lb mahi-mahi fillet, skinless and boneless, cut into ½-inch cubes
- 1 cup seedless watermelon, diced
- ½ cup cucumber, peeled and diced
- ¼ cup red onion, finely chopped
- 1 jalapeño, seeded and finely minced
- ¼ cup fresh cilantro, chopped
- ½ cup freshly squeezed lime juice (about 4 limes)
- ¼ teaspoon sea salt
- ⅛ teaspoon freshly ground black pepper
Instructions
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1In a glass or non-reactive bowl, combine the mahi-mahi cubes with the freshly squeezed lime juice. Ensure the fish is fully submerged. Cover and refrigerate for 20 minutes, or until the fish turns opaque.
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2While the fish is marinating, prepare the watermelon, cucumber, red onion, jalapeño, and cilantro.
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3Once the mahi-mahi is opaque, drain off most of the lime juice, leaving a little to keep the ceviche moist.
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4Gently fold in the diced watermelon, cucumber, red onion, jalapeño, and cilantro. Season with sea salt and black pepper.
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5Serve immediately, garnished with extra cilantro if desired. Enjoy chilled as an appetizer or light meal.
Approximate Information for One Serving
Nutrition Disclaimers
Number of total servings shown is approximate. Actual number of servings will depend on your preferred portion sizes.
Nutritional values shown are general guidelines and reflect information for 1 serving using the ingredients listed, not including any optional ingredients. Actual macros may vary slightly depending on specific brands and types of ingredients used.
To determine the weight of one serving, prepare the recipe as instructed. Weigh the finished recipe, then divide the weight of the finished recipe (not including the weight of the container the food is in) by the desired number of servings. Result will be the weight of one serving.
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