A seasonal pond will be exposed to UV light and frequently changing temperatures during the off-season, a natural clay bed or concrete liner will crack and lose durability during this time.
A durable liner is ideally resistant to the UV radiation that exposure to sunlight will involve. It'll also be able to handle the frequent maintenance and movement that's involved with ensuring ideal conditions for sensitive fry. It'll also need to be fish and plant safe, especially if the fry are intended for direct human consumption. This means that the material can't leak plasticizers or other chemicals into the water that can kill fish and poison humans. BTL's AquaArmor (https://www.btlliners.com/aquaarmor) is rated by the international NSF as the highest quality material available for transporting or storing water meant for human consumption. Additionally, BTL's products are food and plant safe, ensuring the health of your growing fish.
