The potential of the Caribbean strain Chaetoceros muelleri (CHA-C-04) to be produced and used as diet of two commercially important native scallops (Argopecten nucleus and Nodipecten nodosus) was assessed, using the non-indigenous Chaetoceros calcitrans strain, as a control. Growth and biomass of both diatoms were compared under different culture environments (indoor and outdoor) and culture media (F/2, organic fertilizer triple 15 and humus extract). In addition, their bromatological composition and effect on the physiological condition of the scallops fed with both diatoms were compared. The growth and biomass production of C. muelleri and C. calcitrans were higher under indoor conditions and using the F/2 media. Although the content of proteins, lipids and energy was higher in C. muelleri than in C. calcitrans, its size, organic content, growth and biomass values were not different. Scallops fed with both diatoms strains shows similar values for all of the physiological variables measured, including rates of absorption, oxygen consumption, ammonia excretion and scope for growth. Results suggest that the local strain C. muelleri can be successfully produced and used in the diet of A. nucleus and N. nodosus, but do not offer productive advantages.