Can 4 week old betta fry live in a mason jar?

Yes, 4-week-old betta fry can live in a mason jar temporarily, but it is crucial to ensure the jar is large enough to provide adequate space for swimming and growth. The water should be clean and properly conditioned, with regular changes to maintain water quality. Additionally, it's important to provide a source of heat and appropriate food to support their development. However, for long-term care, a larger tank with filtration is recommended.