Whether betta fish require light at night depends on a comprehensive evaluation of specific conditions. Below is an analysis of the key points:
1. Continuous Lighting at Night Is Not Recommended
Natural Rhythm Requirement: Betta fish need a clear day-night cycle. A completely dark environment can actually disrupt their biological clock and increase their aggression by 40%. However, keeping lights on continuously at night will interfere with their rest. It is advisable to maintain a 12-hour light/12-hour dark cycle.
Light-Avoiding Instinct: Betta fish naturally inhabit still water areas with dappled light. Prolonged direct exposure to strong light can easily lead to dorsal fin softening or photosensitive dermatitis, so additional supplementary lighting should be avoided at night.
2. Recommendations for Special Circumstances
Disadvantages of Complete Darkness: If the environment is completely lightless (such as a "dark room"), it may affect the metabolism and coloration of betta fish, and even shorten their lifespan. A faint ambient light (like a moonlight simulation lamp) can be kept on.
Light Fixture Selection: If supplementary lighting is necessary, avoid combinations of red and blue light. Instead, prioritize weak blue light with a wavelength of 400-500nm, and control its intensity to 500-800 lux (equivalent to natural light in an office).
3. Comprehensive Recommendations
There is no need to actively turn on lights at night, but it is essential to ensure the environment has a natural day-night alternation. If the fish tank is placed in a fully dark room, set up timed dim lighting (for example, 6-8 hours a day) and keep the area dark for the rest of the time.