Each year at this time, the rainy season begins in ernest, and to take advantage of its free pristine waters, and get no effort water changes,
I have set up split lengths of bamboo that funnel water dripping off the surrounding foliage and eaves directly into the tank.
Because that foliage has been bone dry for months, the first rains leach a glut of tannins with it, tinting the water very deeply. Sometimes it's so dark, even seeing a few inches into the tank is difficult.
But this is also happening in nature, and seems to a phenom where the anti-bacterial effect, purges pathogens that have built up over the long dry months. I welcome the temporary visual inconvenience.
Although I can't see much of what is going on in the tank, I randomly snap flash pics, just to get a glimpse.
Sometimes getting lucky, and catch things right, like framing the catfish profile in the upper middle area of the shot above.