In this gorgeous and healthy tuna steak recipe, the fish is cooked with Mexican-inspired spices and served with sautéed red peppers and zesty fresh avocado and coriander salsa. This dish is Paleo, gluten-free, Whole30, and low-carb.

Spiced Mexican Tuna Steak
In my quest to eat more fresh fish and expand my dinner repertoire beyond salmon, I decided to make a recipe with tuna.
This recipe features tuna steaks grilled with coriander seeds and lime zest brown butter (ghee or olive oil can also be used for a Whole30 version) and served over cumin and paprika-spiced onions and red peppers, and topped with zesty avocado salsa.
It’s a popular recipe with my readers and is perfect for your weekly menu planning.

Which Tuna To Use In This Recipe?
Tuna steaks can be replaced with salmon, cod or any other fish fillets you prefer or can purchase. If using tuna, please read some notes below.
Tuna fish, regardless of its type, is considered overfished around the world. It doesn’t mean you should stop eating tuna altogether but you need to be able to make smarter choices so we can enjoy tuna in safe amounts for many generations to come.
Avoid the most vulnerable and threatened Bluefin tuna. Albacore tuna caught by pole is the best option, as is Skipjack tuna as they exist in almost every ocean in large shoals and reproduce quicker. Skipjack tuna is primarily used as ‘light tuna’ for canning.
Tuna is high in protein and omega-3 fatty acids but some bigger, deeper water tuna varieties are known to contain higher mercury levels and should be eaten in small amounts. Stick to smaller, shorter lifespan tuna fish caught by pole-and-line, or trolling in certain regions where the supply is ample.
Make sure to check out Good Fish Bad Fish for best Australian choices (it’s a great site with alternatives, cooking methods and so on).
My Simple Guide To Eating Tuna
- Buy tuna 1-2 times per month.
- Chat to your fishmonger and find out the type of tuna they’re selling and where it’s from.
- Educate yourself about the best type of tuna to purchase in your country.
- Make smarter choices when purchasing canned tuna.
- Tell your friends and family to do the same.
More Healthy Fish & Seafood Recipes
- Budget-Friendly Salmon Loaf with Cucumber Dill Salad
- Hawaiian Lomi-Lomi Salmon Salad
- Italian Prawn Arrabbiata with Zucchini Noodles
- Tuna & Sweet Potato Salad (Paleo, Whole3)
- Baked Japanese Salmon Balls
Full Recipe
Find the full list of ingredients, instructions, and a nutritional breakdown below. If you have questions or cook this recipe, please let me know in the comments, and make sure to rate this recipe so it’s easy for others to find.
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Mexican Tuna Steak, Sweet Red Peppers & Avocado Salsa
Ingredients
For red peppers
- 1 tablespoons olive oil
- 1 medium red onion sliced
- 1 medium red pepper capsicum/bell pepper, sliced
- 2/3 teaspoon sweet paprika powder
- 2/3 teaspoon cumin powder
- A good pinch of red chill flakes
- 1 large garlic clove diced finely
- 1 tablespoon apple cider vinegar or other type of vinegar
For tuna steaks
- 1 tablespoon olive oil or coconut oil
- 1 tablespoon butter or ghee
- 1 teaspoon coriander seeds or coriander seeds powder
- 2 tuna steaks about 150 g each, 1-cm thick, sourced with sustainability in mind
- 1 lime
- A pinch of sea salt & black pepper
For avocado
- 1 large avocado ripe, chopped
- 2 tablespoons fresh coriander cilantro, chopped
- Some lime juice about half a lime
- A little pinch of sea salt
Instructions
- Sprinkle tuna steaks with sea salt, black pepper and drizzle with olive oil on both sides. Set aside.
- Heat 3 tablespoons of coconut oil in a frying pan over medium-high heat. Add the onions and peppers, cover with a lid and cook for 5 minutes, stirring a couple of times. Add paprika, cumin, chilli, garlic, vinegar, a good pinch of salt, and about two tablespoons of water. Mix through and cook for 5-7 minutes until softened and slightly browned. Remove to a plate, or use a different frying pan for tuna steaks.
- Grind the coriander seeds with a mortar and pestle or use coriander seed powder instead. Heat up a little oil and butter (or ghee) to sizzling hot in a frying pan. Add coriander seeds and the zest of one lime (about a teaspoon of zest). Stir through to infuse with the flavours. Add the tuna steaks and turn the heat down to medium. Drizzle with juice from half a lime and cook for 2 minutes on each side (more if you like it well done and less if it’s super fresh and you like it rare). Use a spoon to bathe the steaks in the buttery, lime sauce they’re cooking in.
- Combine avocado and fresh coriander and season with a little sea salt and the remaining lime juice, about one tablespoon.
- Assemble red peppers on the serving plates. Place tuna steaks and top with avocado salsa and more red peppers. Squeeze extra lime juice and drizzle with a little extra virgin olive oil just before serving.
This is a great and easy recipe. I make tuna steaks regularly, but this really hit it out of the park! So fresh and delicious.
Thanks!
This used to be one of my favorite summer recipes! I ate it all the time when I was younger and more health-conscious. I’m trying to get back into cooking and eating healthy and could not remember the details to this recipe for the time of me. I have been scouring the internet for over a week and am soo happy I finally found it!!! Just added the ingredients to my upcoming Instacart order. So excited!!
Enjoy, Meg! Happy you managed to rediscover this delicious dish.
Fantastic flavors.
This is absolutely delicious! My husband can’t eat peppers so I substituted Mexican squash and it turned out great. This is definitely going to be added to my list of go-to recipes. Thank you!
Thanks, Beth. Mexican squash sounds delicious as well. I’ll have to look it up now 😉
Hi – I’ve tried this a couple of times and it is completely delicious! However, the carb count seems to be quite high (is this net carbs or should I deduct the fibre)? I wondered whether it is possible to sub out any of the higher-carb ingredients and if so which alternatives might work best?
Thank you for a delicious recipe!
In the nutritional breakdown, you can see carbs and fibre. You deduct the fibre and you will get net carbs, so it will be about 12 g per serving. Most of the carbs are coming from the onion, red peppers, avocado. Just to give you an idea of what’s contributing: 1 medium onion – 10 g carbs (8 g net carbs), 1 sweet red pepper – 7 g carbs (5 g net carbs), 1 avocado – 17 g carbs (4-5 g net carbs), plus garlic, apple cider vinegar, lime juice add a little more. You could make it without the onion or use half an onion. Red peppers are kind of what makes this dish so tasty as they add a little sweetness so there isn’t another substitute. You could also do grilled asparagus or zucchini instead of peppers. It won’t be the same flavour but will still be lovely and nutritious. I hope this helps 🙂
Irena
My husband and I love most seafood but especially tuna and are always looking for new recipes. This was outstanding! Better than high quality restaurant. I will serve this to impress guests.
Thank you and I am so happy it pleased everyone 🙂
Nutritional facts?
I, myself, didn’t enjoy but all six kiddos loved it. So two stars for me and five for the family.
What a tasty and healthy meal. This recipe is restaurant quality and Whole30 compliant to boot! My husband and I loved it and I will be making it again in the near future!
Thank you for such a lovely feedback. I do agree with you, it is something you’d be happy to pay for. xo
Made this tonight for dinner and it was amazing! It was packed with so much flavor. I love anything with lime and I used plenty. The only thing I did different was adding jalapeno, a little onion, and tomato to the avacado making it more quac like. Thanks! This will now be on a regular rotation!
Thank you!!! Glad you enjoyed it. I love lime too 🙂
Utterly delish! I don’t often rave about recipes, but this was totally fabulous!
Thank you, Jane! Very kind of you 🙂
Delicious! Thanks for the next excellent dish
This was outstanding! We made with swordfish twice now. Simple, elegant and super flavorful!
Thanks Melissa, glad you enjoyed it. Elegant is a really nice way to describe it too 🙂
Thank you for this recipe. I came across it quite by chance a few years ago and I’ve lost count of the number of times I’ve made it since then. It’s wonderful. Thank you so much.
Thanks Rob. Much appreciated 🙂
Great recipe! We loved it! Thanks!
Thanks Trish. Irena x
Thank you for this recipe! Although I shamefully admit I was using up tuna that had been in our freezer for a while which was most definitely not sustainable. My very small children adored this recipe, as did my husband and I. We will definitely be making the red pepper component regularly and will try substituting the fish with local chicken next time, as I reckon that would also taste awesome. Thanks!
You’re welcome! Chicken would work perfectly with these flavours.
Oh wow! Made this for the husband tonight. Was amazing. Thank you for sharing. Next time I have friends over I’m going to make it and totally show off!!!
Thanks Suze! Glad you like it.
Thank you for this recipe, it was delicious! Even my husband who hates fish liked it!
Made this last night! It was delicious!
I look forward to trying other recipes.
Thanks Erin!
Yummy! i will make one of these for my wife. I will surprise her on our anniversary. Thank a lot for the idea! She will definitely love this.
Brownie points!
Wow, I’ve never cooked Tuna before, and this recipe was delicious. I subbed the avocado with cucumber & cherry tomatoes. Thanks for all your great work. I also use your cookbook too.
Thank you!!! I am glad you liked the tuna. You can also use any fish with this recipe.
It was very very delicious, thank you for the recipe! I even added a ball of brown rice, because the steaks were quite small and it was so good!
Just tried this recipe as a last minute and it was lovely! Such an easy, fiscally friendly, fresh and inspiring recipe. Love it, thanks!
Just wanted to let you know we LOVE this recipe and it’s a huge family favorite! I posted this recipe as a link on my blog since we like it so much and I definitely gave you ALL the credit! Thanks for an awesome recipe and check out my blog if you are interested!
http://www.greenandgrateful.com/2013/12/paleo-mexican-tuna-steak/
I think I need to stock up on some tuna steaks!
YUMMO! Thank you for this delicious recipe! It tastes so good, I can’t believe it’s healthy!
Just finished this – absolutely delicious! We grilled the tuna instead of sautéing, and made this with ingredients on hand in less than 30 minutes. Thanks so much – even my husband who doesn’t love fish wants this again!
Absolutely delicious. Made it tonight and just finished eating it. My family thanks you too!
This looks amazing – I love the colours in it.
Just made this for dinner and felt immediately compelled to write and say how freaking delicious it is! Loved the flavours and it was so easy to prepare. I did use swordfish instead of tuna but I think they are pretty similar anyway. Even non-paleo husband gave it a double thumbs up.
As a side note, I am very new to paleo and was incredibly excited to find your beautiful website! I am inspired by your down to earth attitude and delicious, easy recipes. Can’t wait til your book comes out 🙂 Thank you!
You’re welcome! I’m glad you enjoyed it and I really hope you like the cookbook when it’s out. 🙂
Please be careful with swordfish Jen, like the Bluefin tuna, they’re also overfished at dangerous levels.
http://www.sustainableseafood.org.au/Sustainable-Seafood-Guide.asp?Keyword=swordfish&active_page_id=695&FirstLetter=&ClassificationID=&ProvenanceID=&SearchButton=Search
Just wanted to post to say how fantastic this recipe is!
I am very much an amateur cook (I can count the meals I have prepared on 2 hands) but had a go at this and the results were brilliant.
My partner said it is the best thing I have ever cooked and the best Tuna steak he has ever had!
Thank you so much
Nice one! Glad you enjoyed it.