Development of Cells Repository of Betta Species: A Tool for Genetic Conservation and Biotechnological Advancement

Thailand harbors a remarkable diversity of betta (Siamese fighting fish); however, their wild populations are threatened by habitat loss and genetic pollution from released ornamental fish. Therefore, effective conservation strategies are needed to extend traditional in situ and ex situ methods, which are resource-intensive and prone to external threats. This study established a practical approach for cultivating cells from ornamental bettas and applying it to 11 wild species collected from their specific type localities in Thailand. Additionally, relevant available data on water properties were collected. Cell isolation was achieved from larval caudal fin bud and adult caudal fin tissues, with larval specimens exhibiting a significantly higher isolation success rate (83.3%) and a shorter initial cultivation period (13.27 ± 3.2 days) compared to adult cells (38.8% success, 24.33 ± 7.8 days initial period). After overcoming senescence, the cell doubling time (DT) was approximately 2 days, and cryopreservation assays demonstrated post-thaw viability over 80%, ensuring the long-term viability. While larval isolation is challenging, adult fin biopsy provides a superior alternative by bypassing breeding and euthanasia. This non-lethal, repeatable sampling method allows for precise species identification via external morphology, offering a highly efficient strategy for conservation. Cell isolation was achieved for 10 of the 11 species, 9 of which resulted in established, cryopreserved cell lines, representing the first maintained cell lines from larval and adult tissues of Betta species and providing a novel, valuable resource for both biotechnology and the crucial biodiversity conservation of this important freshwater fish of Thailand.