I've been in various parts of this hobby for over 30 years. One thing that comes up frequently is the positive impact sunlight has on most fish. It brightens their color, provides surface algae for grazing and maintains water parameters better than sun deprived systems. I've noticed that the serious breeders in Thailand use outdoor tubs that are lightly shaded. I bread Betta splendens a few years ago and tried to replicate their sunny methods by mounting 60watts of LED's over the tub. The Betta grew wonderfully. I later put a Ranchu in the tub and actually forgot about him for over a month. I finally went to check on the tub ,expecting to find only remains of the fish. It had thrived, and taken on a strong swimming manner and nice dark red/orange color. The tub has a large sponge filter and an airstone. The sides of the tub are covered in a smooth green paper like coating that can be pealed off in sheets.