Do All Tuna Fish Have Scales and Fins? Species Guide

Tuna is one of the tastiest kinds of fish out there, and it has many health benefits. But does it have scales and fins? And, is it considered kosher (pure for consumption) in Jewish tradition?  …

yellowfin tuna with scales

Tuna is one of the tastiest kinds of fish out there, and it has many health benefits. But does it have scales and fins? And, is it considered kosher (pure for consumption) in Jewish tradition? 

All tuna fish have scales and fins. Fins help the tuna breathe and swim, while scales protect the fish from predators. Since tuna fish have both fins and scales, they’re considered kosher (permissible to eat) in Jewish tradition. 

In this article, I’ll cover over five variations of tuna and look into their scales in detail. I’ll also discuss whether each tuna type is certified kosher, too!

Do Tuna Fish Have Scales?

Scales on tuna fish aren’t as apparent as some other fish types, such as tilapia and pomfret. So, does tuna even have scales? If so, why can’t you see them? 

Tuna fish have scales, which are known as “scutes.” These scales are small and few. They’re flat and hard, making them invisible to the naked eye! But, all variations of tuna have scales that can be easily perceived through a microscope. 

fresh bluefin tuna fish in the market

Speaking of tuna variations, let’s briefly look at a few of them and the type of scales they possess. 

  • Bluefin Tuna: The bluefin tuna is one of the highest-demand tuna variations out there! It’s trendy in far-east Asian countries in seafood dishes like sashimi and sushi.

    They have scales all over their bodies with a blackish-blue back, bright silver flanks, and a yellowish stomach area. Their fins are — you guessed it — bright blue! 
  • Albacore Tuna: Albacore tuna is also commonly known as longfin tuna and has a streamlined, dark-colored body covered in tiny scales. It’s characterized by its big mouth and large eyes. 
  • Ahi Tuna: Ahi tuna is very similar to yellowfin tuna. They have streamlined bodies with large eyes. There are only a few scales behind the corselet, though a band of large scales circles its head. 
  • Yellowfin Tuna: The yellowfin tuna is barely distinguishable from the Ahi, and only the pros know the signs to look for to tell these two apart. They even have similar scale patterns and sizes. The most significant difference is that the yellowfin tuna has smaller eyes than the Ahi. 
  • Skipjack Tuna: A medium-sized streamlined fish from the tuna family, the skipjack has many names like cakalang, katsuo, balaya, mushmouth, oceanic bonito, vector fish, and striped luna. It’s also called “light tuna” when canned.

    It has thick scales along its lateral line and corselet — but nowhere else on its body. 
open canned tuna with fork

Does Canned Tuna Have Scales?

All types of tuna have scales, even though you can barely see them. But what about canned fish? Are there scales in there? 

Most canned tuna products do not have scales in them. Skin, dark-meat portions, and hard parts like bones and scales are generally removed from tuna before it’s packaged into cans. 

During the cleaning and preparation phase before canning the tuna, the fish get sorted by size, pre-cooked, and cooled, followed by de-boning and removing their skin (source: ScienceDirect). 

As you can imagine, tuna’s small scales get removed along with its skin.

The next step is to separate the meat into light and red meat, the former getting picked for the canning process while the latter is mostly processed into pet food. The loins for human consumption are then cleaned well before getting canned (source: Colorado State University). 

Does Tuna Have Both Fins and Scales? Is It Kosher?

This question is popular among fish lovers within the Jewish community. So, are all types of tuna considered Kosher (pure for consumption)? 

Tuna has fins and scales and is kosher. The Jewish law requires fish to have both fins and scales to be permissible or “pure” for consumption. While tuna fish has very few scales, they are considered certified Kosher since all tuna types meet both conditions. 

Unlike fowl or meat, the Jewish rulings do not require fish to be slaughtered and salted to be consumed. All tuna fit the kosher standard and can be served in a Jewish home in any shape or form (source: Chabad). 

Canned tuna is also kosher as long as the meat used as a key ingredient comes from tuna. However, to ensure that the specific canned product you buy is kosher, check the ingredients list to see if the company has added other types of fish into the mix and whether they are non-kosher. 

Examples of non-kosher fish that may sometimes be mixed with tuna are:

  • Shrimp 
  • Lobster 
  • Crabs 
  • Swordfish 
  • Eel 
  • Shark 
  • Oyster 
  • Shellfish 
  • Clams 
  • Skate 

Here are some tips to keep in mind to make sure what you buy is certified kosher tuna: 

  • Only buy your seafood from a place that falls under rabbinic supervision. However, such an establishment might not be accessible to everyone. If that’s the case with you, follow the next few tips. 
  • Buy unprocessed, fresh tuna with scales still attached. This way, you’d know that the fish you’re buying and consuming has scales and fins, making it certified kosher by nature. It reduces your risk since the industry uses the same name for different fish varieties, which may or may not be kosher. 
  • Look for the certification of a reliable kosher agency on processed tuna products. These include smoked, canned, and pickled tuna — make sure they’re certified by a licensed rabbi or a reliable kashrut supervision agency. 
yellowfin tuna with scales and fins

Can You Eat Tuna Scales?

Now that you know that all tuna fish have scales, the next question that arises is whether they’re safe and enjoyable to eat. 

You can eat tuna scales, but you probably wouldn’t want to do so. Tuna fish skin and scales are very tough, and while they’re not particularly unhealthy for consumption, they’re not enjoyable or tasty either. 

If you choose to eat tuna skin and scales, make sure to cook them as harmful bacteria live on the outer layer of the fish. 

Note: Fish scales generally taste like nothing if consumed raw or uncooked. One Quora response described it as “eating a piece of plastic” (source: Quora).

In this article, I’ve tried to cover all there is to know about tuna, whether or not each of its types has scales along with their kosher status. I hope you found the information helpful, and happy tuna-eating!