The study of some fish species has such a convoluted history that it will likely never be possible to untangle it completely. In 1822, the Scottish ichthyologist Francis Hamilton described two tiny barbs from the Ganges River basin in India: Puntius gelius and Puntius canius. The two were practically confused with one another from the very beginning because they have very similar coloration. Today, both are classified in the genus Pethia. The key difference lies in scale size. The scales of P. canius are almost twice as large as those of P. gelius.
P. canius is one of the smallest barb species in India. Males rarely grow longer than 2.5 cm, while females are slightly larger. The record of 5 cm total length, which is occasionally cited for both this species and P. gelius, is likely due to confusion with other species.
Incidentally, it has recently come to light that P. canius belongs to an entire complex of very similar species. The names of these species are the previously mentioned Pethia gelius, Pethia canius, and, added in 2013, P. aurea. These three species are virtually indistinguishable to the naked eye, at least as juveniles; in the trade, they are therefore all commonly referred to as “P. gelius” . The complex also includes the drab-colored P. guganio. What these species have in common is that—like the harlequin barbs—they spawn belly-up under plant leaves.
No matter which variety of this species you purchase, they are delightful, extremely peaceful schooling fish. You’ll do them a great favor by adding humic substances to the water (dead leaves, peat, alder cones), and you should allow some mulm to accumulate in the aquarium. Otherwise, they are completely undemanding little creatures.
Maximum size: approx. 2.5–3 cm; Temperature: 18–28°C; pH and hardness: not important for general care (tap water), but soft and acidic for breeding; Diet: omnivorous; Social behavior: peaceful schooling fish.
We have also made a small film about these fish, which you can watch here: https://www.youtube.com/watch?v=agYvTweMZQY
For our customers: Depending on their size, these animals are listed under codes 399101 through 399103 on our stock list. Please note that we supply exclusively to wholesale customers.
Text & photos: Frank Schäfer
