The group of 4 is still in that 2.5g with a single 13wt 03 PC bulb. There is a tiny amount of natural sun coming through the window but it is negligible due to UV films on the glass, etc.
There are 2 in my main system, they have not show any sustained reaction to light, 400w or the 75wt incan grow bulb over my cheato algae. Frankly, I don't think they care one way or another.
Feed them every other day minimum. Keep the pieces smaller then a pencil eraser to avoid the regurg. If you read the thread where they wacked the mollies, one spit up some digested matter the next day.
Mine eat shrimp and fish based meals.