Is it true that the longer you keep your fish in the sun, the better it is?

It's a case-by-case decision

First of all, the purpose of sun-watering is to remove residual chlorine and impurities in the aquarium and to improve the water quality.

Usually speaking, the time of basking should be around 2-3 days is more appropriate. If the water quality is poor, you can extend the basking time appropriately, but too long basking time may lead to too low oxygen content in the water, which is not good for the health of the fish.

Secondly, the basking time should also consider seasonal and climatic conditions.

In summer and warm climates, the time of basking can be appropriately shortened because chlorine can be evaporated more quickly. In winter and cold climates, on the other hand, the tanning time should be lengthened because the evaporation of chlorine is slowed down.

Additionally, the duration of basking time is also related to the water volume of the tank and the number of fish. Tanks with a large volume of water and a large number of fish will require a longer basking time to ensure that the water quality is sufficiently improved.