There’s something fishy about seafood allergies. While shellfish and finned fish may live in the same aqueous environment and share unique qualities, these critters are far from identical. From allergen-causing proteins to structural components, these water-loving species are different in numerous ways, but both should be approached cautiously as they can result in severe allergic reactions.
When it comes to finned fish versus shellfish, the distinction between the two can be confusing. As the name implies, shellfish have shells to protect their delicate, invertebrate bodies that lack major structural components. The broad classification of shellfish includes two subcategories: mollusks and crustaceans. Crustacean typically feature a central body with limbs like those on lobster and crab whereas mollusks have a more simplistic, limbless body like scallops and clams. Both mollusks and crustacean differ from finned fish which encompass any type of vertebrate fish with gills. Finned fish include common cold-blooded creatures like salmon, trout and tuna along with sharks.
Both types of fish can spark allergic reactions in some individuals. Finned fish contain a protein, parvalbumin that initiates the allergen cascade when inhaled or consumed. Parvalbumin can be found among many different species of finned fish. According to the University of Mississippi, salmon, tuna and halibut are most likely to cause allergic reactions among finned fish. Shellfish allergies often result from ingesting tropomyosin. Since the fish and shellfish do not share the same reactive protein, an individual can be allergic to finned fish without being allergic to seafood. For example, a severe anaphylactic reaction caused by scallops may not be produced when exposed to lobster. Individuals may also be able to tolerate specific species of finned fish while being allergic to other fish species.
Although fish and shellfish can cause life-threatening allergic reactions, they are swimming with fascinating facts. A couple of notable ones include:

  • King mackerel, swordfish and tile fish comprise the top three mercury-containing fish.
  • Finned fish have taste buds in their mouth and on their fins and lips.
  • In the shellfish world, clams and oysters are good sources of iron, zinc and magnesium while shrimp, crab and lobster are most responsible for causing allergic reactions.
  • Turns out having the memory of a goldfish may not be so bad after all; according to National Geographic, goldfish can learn and remember patterns making them trainable critters!

Finned fish and shellfish have beneficial nutrients and exciting characteristics, but should be cautiously approached when food allergies are a concern. While brushing up on your fun fish facts is a great use of time, allergic reactions can make these serious matters. Cast your reel with caution when dining in or around these water-loving species.