This research aimed to determine the reproductive potential of medaka fish (Oryzias profundicola), including fecundity, egg diameter, and gonado somatic index (GSI). This research was carried out from January to June 2022. The sampling location was Lake Towuti in South Sulawesi. Medaka fish sample collection was carried out at each research station using a modified bag seser net with a mesh size of ¾ inch, a total length of one fishing gear unit of 15 meters, a height of 1.50 meters, and a bag length of 3 meters. The fecundity of medaka fish at station 1 (Tanjung Timbala) ranged from 27- 87 eggs (56± 15 eggs) for TKG III and 65- 175 eggs (104± 21 eggs) for TKG IV, while the total fecundity recorded 15,157 eggs. Station 2 (Tanjung Lengkobutangan) fecundity for TKG III ranged from 31- 84 eggs (47± 11 eggs) and TKG IV ranged from 97- 182 eggs (153 ± 20 eggs), and total fecundity was 11,369 eggs. The diameter of medaka fish eggs in Lake Towuti at all stations was found to range between 0.03 & 1.19mm, with the highest frequency for TKG III in the range of 0.03- 1.08mm, while for TKG IV, it was in the range of 0.15- 1. 19mm. The IKG tendency for female fish is relatively greater than that of male fish, except in April and May at station 3 (Tanjung Bakara) and in April at station 5 (Tanjung Tominanga). Reproductive potential is the product of the number of fish and the average fecundity. The reproductive potential of medaka fish at station 1 was 15,157 eggs, station 2 was 11,369 eggs, station 3 was 10,723 eggs, station 4 was 14,842 eggs, and station 5 was 18,385 eggs.