In the present work, the feasibility of fattening Oreochromis niloticus specimens on a pilot scale in a geothermal water resource located in the Southeast of the province of Buenos Aires was analyzed. Before placing the culture units, physical and chemical characteristics of hot spring were studied to evaluate its suitability for tilapia farming. In the experimental stage, two hundred specimens with an average weight of 14.5 ± 1.8g were placed in two floating cages (1.30x1x1m) (100 individuals per cage) and they were harvested at 140 days. The specimens were fed 3 times a day with a commercial pelleted feed with a content of 35% of proteins. Monthly samplings were carried out to evaluate growth (weight and total length), survival, and water samples were collected to measure their physical-chemical characteristics. The results of the water analysis showed a high quality in the hot springs (Simplified Water Quality Index=88). The fattening results showed an average final weight of 423-435.9 g, a survival of 87-91%, a SGR 1.47- 1.49% / day and  the FCR was estimated at 1.05-1.07 for each cage respectively. We can conclude that this hot spring has the necessary water conditions to obtain excellent weight gains during the fattening period for the O. niloticus specimens. The present study represents the first Nile tilapia culture in the southernmost thermal waters, setting a precedent for future ventures in the area.

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El presente trabajo tuvo como objetivo evaluar el crecimiento de juveniles del pez ornamental  H. bimaculatus, Cichlidae, utilizando residuos industriales de langostino argentino y cebada cervecera, con complemento de algas en el alimento. El cultivo se realizó en un sistema de recirculación de agua a escala de laboratorio. Se evaluaron los parámetros peso y largo total de los individuos, la supervivencia, la calidad del agua y el funcionamiento del sistema empleado.   Si bien se hallaron diferencias significativas (p ˂0,05) para ambas variables al compararlas con el alimento control, 47,5 % de proteínas, el crecimiento con el alimento alternativo fue positivo,  tasa de crecimiento específico 2 mg/día, y la sobrevivencia muy elevada, 98%. Los residuos de langostino y cebada podrían ser  utilizados como materias primas  en alimentos formulados para esta especie, reemplazando parcialmente a la harina de pescado, de forma más amigable con el ambiente y con alta disponibilidad regional.