Join Date: Oct 2010
Location: Victoria, Australia
I personally wouldn't add another pleco to a tank that size. Even though they are much smaller than a Common Pleco, an adult Bristlenose Pleco still grows to a decent size. I had an adult Peppermint Bristlenose in a slightly larger tank, and it just felt cramped. In addition, they produce a large amount of waste, so you need filtration capable of handling the bioload.
I do think plecos can be territorial, but I'm not 100% certain as my experience with these fish is limited.
Kuhli loaches are social fish. For them to be comfortable and exhibit natural behaviour, you would need at least six of them.