Barbus pentazona grows to over 2"/50mm and looks vaguely like a slightly longer slightly thinner tiger barb with more stripes. A much more peaceful fish though, also a good deal more sensitive. Very susceptible to white spot. Once established in a well maintained tank however, is a long lived trouble free species. One I always have in fact.
There are 4 recognised sub species, B. pentazona pentazona with 5 stripes, B. pentazona partipentazona with 4½ stripes, (the stripe under the dorsal fin does not go all the way down), B. pentazona hexazona with 6 stripes and B. pentazona rhombocellatus which has 5 stripes, but the stripes divide in 2 part way down then rejoin again at the bottom so it looks like a row of diamond shapes - a truly good specimen is a treasure.
They stress easily and should not be kept with anything to boistrous. Other peaceful Barbs, Tetras and ideally Rasboras make good tank mates.