This study presents some traits of the Aphanius ginaonis life history in the Geno hot spring and explains the potential risks of its extinction. Sampling was from March 2009 to February 2010. A total of 61 males and 71 females were measured (total length) and weighed, with data on reproductive biometry also taken. Growth parameters were determined in addition to weight–length relationships: W (t) = 0.012TL3.42, R2 = 0.96 for females and W (t) = 0.0101TL3.38, R2 = 0.94 for males. A. ginaonis females showed an asymptotic total length (TL∞) of 53.03 mm; the growth coefficient, K (year−1) 0.15, t0 (year) 1.01; and natural mortality coefficient M (year−1) 0.62. In males the value for TL∞ was 48.83 mm; for K (year−1) 0.2, t0 (year) 0.44; and M (year−1) 0.49. The relationship between absolute fecundity and fish size (total length, body weight or age) showed a strong correlation to body weight. The A. ginaonis population is threatened with extinction – and a co-management in cooperation with the local population for strong protection measures is urgently needed.