Barbus gelius, sometimes called the Dwarf Golden Barb. A peaceful but very active sprightly little fish that stays small.
I had a huge row in the late 1980's because a person who will remain nameless, (was director of the aquarium at London Zoo, surname begins with A, anyone involved with the technical side of the hobby will now who I mean!), decided to re-classify the "species" as three distinct species. I spent about two years breeding the various "species" to demonstrate that they were all the same species with regional variation.
I also have a soft spot for Cæcobarbus geertsii, someties called the Congo Blind Barb.
I was involved in the species maintenance program for this fish in the same period. Not the prettiest of fish. The thing I remember most of all was the amount of paperwork to be done to be part of the program. Documenting the parents of each batch of fry, the gentic relationships between batches, the water chemistry to extreme precision, (the fish breed easily in tapwater for goodness sake!). I also recall the annoyance of MAFF inspections at short notice in order to maintain the licence to keep the CITES species. Was all coordinated by Reading University.
Generally, I have kept barbs for over 40 years, and rarely have been without one or more species. Barbs look like fish should look, diamond shaped with short based errect fins and scales, only Rasboras equal them in my view.