In a small town on the Catalan coast, the Balfegó family has been fishing red tuna in the Mediterranean for five generations, becoming one of the largest producers of the fish in the world. Yet, even with this pedigree, the brand has largely been unknown to consumers. So, they turned to Barcelona firm El Equipo Creativo to design a restaurant that highlights the richly textured fish in an ethereal underwater-inspired space.

Tunateca Balfegó—the family’s first restaurant dedicated solely to red tuna—sits on a busy commercial artery on Barcelona’s Avenida Diagonal, but inside there’s a serene quality thanks to a palette of rich, ocean blue hues and subtle red tones. Split up into zones, the blue room serves as an underwater oasis. Here, a large, undulating ceiling resembles a school of fish swimming overhead, “making us feel, if possible, even more immersed in the sea,” says the firm’s cofounder, partner, and creative director Natali Canas del Pozo. “The result is an exquisite setting made possible by organic illumination with subtle movements and changes in intensity, which bring the installation to life.” Three oval stainless steel bars with dark stone tops “remind us of the large tuna swimming through the space,” she says, while the busiest area is nestled around a 16-foot-long sushi bar where surrounding tables vary in form to recall the fish’s different cuts. In addition, dark red seats add “an interesting contrast to the deep blue space,” she explains.

Because the family planned to host ronquero (the traditional manual dissection of tuna) sessions, they required a space large enough for that work to take place. The trapezoidal ceramic tiles that wraps the space—a nod to the tuna’s shiny blue and silver scales—gives the area a dramatic and clean feeling, and “large, dark red boxes serve as a color contrast,” she says. Private rooms on the upper floor have subtle reddish hues for added warmth, while golden metallic sliding doors separate the space. The walls and ceiling are clad in perforated wood but the star of the room, and the restaurant’s true protagonist, is a large red wooden table that forms the subtle outline of a golden fishbone.