The Checker Barb, Barbus oligolepis, good specimens at least, can have bright red fins, with a thin black border. Females are less colourful, and may have clear, or yellowish fins, although a good female will also have red fins, though often lacking or having a very faint border. There are a huge number of very poor specimens around that have almost no colour in the fins at all.
B. oligolepis has quite large scales, the root of which, (leading edge), has a darker, in good fish, black mark. Even poor fish show this to a certain extent. The "checker" name comes from this marking.
They are small fish, rarely growing to 75mm/3", although some sources quote twice this. In my experience, they breed readily at 60mm and after many years in large tanks have not grown to more then 75mm. They are a longer bodied fish than Tinfoils. A group of decent quality B. oligolepis is quite a sight.
Tinfoil Barbs, Barbus schwanefeldi have red fins, but usually without the continuous black border of oligolepis. When very young, they can have a darker top to the dorsal, and outer lobes of the caudal, this tends to fade.
The scales are quite small, and uniformly silver. When young the diamong shape of the body is quite apparent. As they grow, which they will do at an alarming rate, their huge size, easily 300mm/12" makes distinguishing the two obvious.
Both are peaceful shoaling fish, but of course, a decent shoal of Tinfoils requires a very large tank. Although peaceful, they are large and will swallow smaller fish.