Researchers have often suggested that abiotic conditions influence interactions among salmonids in general and between brook troutSalvelinus fontinalisand rainbow troutOncorhynchus mykissin particular with brook trout having an advantage at lower temperatures and slower, deeper habitats (i.e., pools). In artificial stream channels, we tested whether temperature (13°C and 18°C) and macrohabitat (riffle and pool) affected aggressive interactions, foraging success, and growth rates of interspecific pairs of juvenile brook trout and rainbow trout. Brook trout were significantly more aggressive, captured significantly more prey, and had significantly greater growth rates than rainbow trout at both 13°C and 18°C. The differential effect of temperature on aggressive interactions between the species was significant; a greater difference was found at 13°C than at 18°C. However, this did not lead to a temperature-based shift in behavioral dominance because brook trout dominated rainbow trout at both temperatures. Overall, we recorded significantly greater growth rates and significantly fewer aggressive interactions and prey captures at 13°C than at 18°C. Macrohabitat did not significantly affect aggressive interactions or foraging success, but growth rates were significantly greater in riffles than in pools for both species. Macrohabitat had no differential effect on brook trout and rainbow trout. Our results suggest that differential effects of temperature and macrohabitat are not sufficient explanations of observed brook trout and rainbow trout distributions in streams.