This study aimed to determine the biomass culture capacity and total carotenoid content of heterotrophic marine microalgae genera, including the genus Schizochytrium and Thraustochytrium on the coast of Tra VinhProvince. Five strains of these genera, DH41.79, CN27, DH10, CN15, and CN47, were cultured for biomass and carotenoid content. The study showed that the cell density of CN47 was highest with different periods under three different dilution levels (10%, 20%, and 30%), with a positive relationship between cell density and dryweight of algae strains (R2 ≈ 1 > 0). Besides, the results indicated that all densities of strain CN47 showed carotenoid content of this strain (7,613 µg/kg) was significantly higher than that of the 04 remainings and previous studies. The research results contribute to the foundation for scientific works on the heterotrophic marine microalgae Thraustochytrids, which have a high potential for applications in biomass production,extraction of high-value nutritional compounds for aquaculture, towards sustainable development through replacing fish oil sourced from natural exploitation in Tra Vinh Province.