This study was conducted to determine the bacterial composition and its effect on Artemia performance in various Artemia biomass culture conditions. Newly hatched Artemia franciscana were cultured in 1.5L plastic bottles containing 1L of culture medium, with a density of 200 nauplii/L and salinity 30 ppt, and lasted for three weeks. In the first two days after stocking, Artemia was fed with Chaetoceros sp. Afterward, Artemia-formulated feed was used as daily food. In biofloc and bacteria treatments, the C/N ratio was regularly manipulated in the Artemia culture medium from day 5 and onwards. The statistical analysis results showed that culture conditions, as well as the bacterial development in those culture batches, affected Artemia performance. The best survival rate, individual length, and biomass were obtained in the seawater and biofloc treatment after 21 days of culturing. The total bacteria varied from 83–146 × 10³ CFU/mL, with the highest value seen in the biofloc (BF) treatments. The biofloc treatments had a significantly higher bacterial density than the non-biofloc treatments. Nitrosomonas was better developed in seawater (SW) while the Nitrobacter was in sea salt (SS) medium.