It contains tannins and other stuff that leaches out of sunken wood, leaves and peat. It makes the water more acidic and stains it brown, much like the water found in parts of the Amazon and other tropical rainforest.
You can achieve a similar thing by adding pieces of driftwood, a small bag of peat in your filter or some autumn leaves (Oak leaves are good I believe).
It just makes you tank water a bit more like the fishes natural habitat where a stream is full of fallen leaves and branches and the water has been filtered through miles of the stuff. The water looks a bit like a weak brew of tea
"Creates clear,"natural",Amazon-biotope conditions in the aquarium. Contains Vitamins: B2,B6,B12, Nicotinicamide, Panthenol, Biotin, and peat extract."
i new it was for amazonian type tanks. one of my 55s has 6 or more angels, and i was wondering what all it would do- breeding? high growth increase? color boost?
Keeping your water pristine with lots of large water changes are all that is necessary. I can guarantee you, most of the angelfish sold at shops are tank bred in tap water.
The best result I've ever seen from any black water mix in a bottle is the lightening of the wallet it causes, thus making it easier to carry. Darker tank=lighter wallet. That's their super secret trade secret.
There are some fish that require soft water to breed (and even fewer to live), but that is achieved by putting them in soft water. Not something ou can buy in a little bottle.
Save your money, see how your angels breed in the tap (treated, of course).
I've tried that before. It is not only just for breeding purposes if you really intend to match the water conditions as that of the wild. It can be used to replicate the environment and adjusting the water parameters closer to that of the wild. The only drawback is its price. Peat, driftwoods and almond leaves work just as much as blackwater extracts do. They're still the same thing. Either way works but concerning the expenses, I'd stick with the former.