<p>The slipper lobster (<i>Thenus australiensis</i>) is a promising aquaculture species, yet its nutritional requirements remain poorly defined compared to those of other crustaceans. A preliminary factorial model was developed in this study to quantify the daily protein and energy requirements of juvenile slipper lobsters, with demands partitioned into maintenance and growth components. Using data from two controlled growth experiments at 26&#xa0;°C, regression analyses quantified weight gain as a function of body weight (g BW⁻¹&#xa0;day⁻¹), feed intake, and whole-body composition across juveniles ranging from 5 to 83&#xa0;g wet weight. Whole-body crude protein (CP) and gross energy (GE) content were stable across size classes, averaging 456&#xa0;mg CP g BW⁻¹ and 13&#xa0;kJ GE g BW⁻¹ on a dry-matter basis. Daily maintenance requirements were estimated at 10.8&#xa0;mg digestible protein (DP) g BW⁻¹&#xa0;day⁻¹ and 477&#xa0;J digestible energy (DE) g BW⁻¹&#xa0;day⁻¹, with partial utilisation efficiencies of 0.45 for DP and 0.58 for DE. The model predicts shifting DP:DE ratios across instar stages, reflecting increasing maintenance costs with body size. These findings provide a foundation for defining the nutritional needs of juvenile slipper lobsters and deliver applied insights for feed formulation. By expressing requirements as absolute daily demands, the model offers a practical tool for hatchery and grow-out operations, supporting improved feed efficiency and reduced nutrient waste. The next step in validating and refining the model involves expanding research throughout the entire production cycle. Integrating new information and advances in nutritional needs and feed formulation will further enhance the model.</p>