Be careful with Ancistrus - Discus combination as Bristlenose plecos can (and many time will) hang from Discus sides, causing damage to Discus epidermis.
I bought my first bristlenose as a cleaner for my very first tank. It was tiny and we had no way to tell what sex it was. Now a year and a half later she (10 cm, no bristles) has been moved from my 75 L to my relatively new 180 L tank and is loving it. I have also recently bought a male for her, a male for my 75 L and a little baby for my 40 L. In my experience the males not only have the obvious bristles, but are also darker. Also, I've found the bristlenoses I've gotten younger are more active and don't hide as much. They're brilliant fish that I'll use as cleaners for every tank I set up.
Today, while adding a piece of drift wood to my 340 liter which has about 12 bristle nose plecos and about 20 A. calvus and other shell dwellers, I noticed a young male in a conch shell. He is only about 5 cm long and has 16 babies with him. My water is not acidic, did nothing to it, straight from the tap. This tank was set up 1 month ago, and after trying to breed them before this for years, they did it onw their own. One thing though, the water temp is just about 20°C, not as high as some people say it should be.
I have only been into keeping fish for a relatively short time, about 7 months. The first fish I bought for my first tank, 34 L, was a bristlenose pleco that later on turned out to be female, I was kind of disappointed about this because I wanted one with bristles. So I went to my LFS on a Tuesday and bought a male that was the same size as my female (7-8 cm). When I woke up this morning (Saturday) I discovered my male tending to 25-35 eggs. pH 6.8, temp ~27°C.
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