Two Tone Concolor Hoplisoma (Hoplisoma sp. (Cw217))

Remarks:  While the two tone concolor hoplisoma (Hoplisoma sp. (Cw217), also known as the Rio Tomo hoplisoma, has only recently made its debut in the hobby and has yet to receive an official classification, it has quickly become a fan favorite. One look at a mature specimen and you are almost certain to get hooked, especially if you like Corydoradinae. The two tone concolor hoplisoma takes on a striking appearance upon maturity when in the right conditions with the front half of these robust fish being a dark, slate gray or black while the back half and fins are a nicely contrasting orange. This coloration is present in both males and females making body and fin shape a better tell for sexing them. Females are larger, thicker bodied, and have short, rounded fins. Males are smaller, more stream-lined, and have pointed extensions on their fins making an already incredible fish even more beautiful.

  If you are familiar with the slate hoplisoma (Hoplisoma concolor), you likely have noticed that the two tone concolor hoplisoma is very similar. In fact, the only visual difference between the two species lies in their coloration with the slate hoplisoma having a completely dark gray body. Both species reach the same size, have the same care, and display the same behaviors. This has led many to believe that the two tone concolor hoplisoma is just a locality/color variant of the slate hoplisoma. However, there is evidence to support that while the two are very closely related, the two tone concolor hoplisoma is more likely to be a sub-species of the slate hoplisoma or even an entirely separate sister species.

  This likely separation is because when it comes to color variants in a species, you will sporadically see one appear in a population of “normally” colored animals. If the two tone concolor hoplisoma were just a color variant of the slate hoplisoma, you would see one occasionally be produced from a population of slate hoplisoma and vice versa. Both in wild populations and the small amount of breeding groups in captivity, this has yet to be reported. In fact, the two tone concolor hoplisoma can only be found and is known to be the only armored catfish found in a small tributary of the Rio Tomo, a tributary of the Rio Orinoco, that local fishermen refer to as the Cano Negro. With such heavy separation and the lack of either population producing any of the other, we will likely see them classified in the future as separate species.

  The two tone concolor hoplisoma was previously classified as Corydoras sp. (Cw217), but was reclassified as Hoplisoma sp. (Cw217) upon publication of a phylogenomic analysis in 2024 that reclassified many species in the Corydoradinae subfamily.

  Corydoradinae are small, peaceful catfish that are active shoalers and will stay near conspecifics, making for a lovely sight. They feed by searching through sand with their barbels, making such a substrate necessary for their long-term health. Gravel substrates tend to be abrasive and damage the barbels, leading to infections and an inability to find food. Something interesting to note about the two tone concolor hoplisoma is that while their natural habitat in the Cano Negro is noted to be crystal clear, keepers have found their show their best coloration when kept in tannin-stained blackwater.

  While these friendly catfish are willing to swim with other species of Corydoradinae different from their own, this does not provide the same social need as being kept with members of their own species. Because of this, it is highly recommended to keep at least six of each species of Corydoradinae present in the aquarium and only mix species if one has the space to keep at least six of each.

  Corydoradinae are often looked at as "scavengers," but they should be treated in a similar fashion as the rest of your fish. They are omnivores and require a mixed diet. Sinking prepared foods are readily accepted, as are frozen and live foods such as brine shrimp, blackworms, and bloodworms.