A boat-accessed fish-farm dive off the Barcelona and Maresme coast, with a metal framework that turns a working structure into an easy-to-read exploration site. The draw is the combination of compact architecture, sheltered swimming lanes, and abundant life tucked into holes, pipes, and shaded corners. It works best as a controlled boat day with steady buoyancy, a clear turn plan, and enough attention left for the structure itself rather than open-water wandering.