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

## TL;DR

Scientists developed a way to preserve Betta fish cells for conservation and research, using cryopreservation and non-lethal methods.

## Contribution

The study introduces a practical and non-lethal method for cryopreserving Betta fish cells from various life stages, enabling long-term conservation and research.

## Key findings

- Cells from 11 wild Betta species were successfully isolated and cryopreserved.
- Larval cells showed higher isolation success and faster cultivation than adult cells.
- Non-lethal adult fin biopsy proved to be a viable and repeatable sampling method.

## Abstract

Siamese fighting fish (Betta spp.), Thailand’s national aquatic animal, is world-famous for its vibrant colors and unique behaviors. However, many wild species in Thailand are now threatened, creating an urgent need for effective conservation. In this study, we developed a practical method to collect and preserve cells of the Betta species using ultra-low temperature storage (cryopreservation) for long-term protection. We successfully isolated cells from eleven different wild species while also analyzing the water quality of their natural habitats. A key advantage of our approach is its versatility; we can successfully collect and culture cells from various sources and across different life stages, from young larvae to adult fish. Crucially, our results prove that these cells remain viable and healthy following prolonged storage. Beyond serving as a genetic reservoir for Thailand’s betta diversity, these established cell lines provide a powerful tool for researchers. They allow us to study how bettas remarkably adapt to changing environments without needing to disturb live fish from the wild. This work offers a sustainable path to safeguard the future of these iconic fish.

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.