2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/88532Motivated by the finding that there is some biological universality in the relationship between school geometry and school biomass of various pelagic fishes in various conditions, I here establish a scaling law for school dimensions: the school diameter increases as a power-law function of school biomass. The power-law exponent is extracted through the data collapse, and is close to 3/5. This value of the exponent implies that the mean packing density decreases as the school biomass increases, and the packing structure displays a mass-fractal dimension of 5/3. By exploiting an analogy between school geometry and polymer chain statistics, I examine the behavioral algorithm governing the swollen conformation of large-sized schools of pelagics, and I explain the value of the exponent.25 pages, 6 figures, to appear in J. Theor. BiolPopulations and EvolutionOther Condensed MatterStatistical MechanicsOther Quantitative Biologytext