Hoplisoma caudimaculatum

Small, tidy, and a little bit ridiculous - a pale body dusted with fine spots and one bold dark blotch right at the base of the tail, like it got dipped and pulled out too soon. More vivid than the similis you've probably seen, and a lot more outgoing about it: these cruise the front of the tank in a busy little group instead of hiding in the back. They top out around an inch and a half. I ship them at a proper inch-plus, never fragile babies - a fish that size travels better and settles in ready to eat. Easy to keep, easy to watch, hard not to like.

On paper, it's Least Concern. That label covers the entire Guaporé-Iténez drainage along the Brazil-Bolivia border, and a fish spread across a range that big is hard to worry about from a spreadsheet. The headwaters are another story. A 2026 study looked at 21 streams in the Rondônia stretch of the basin and found hardly any with more than 70% of their forest still standing. The worst were under 3%. Less forest, less canopy over the water.¹ And those small shaded creeks are exactly where corys live. A "Least Concern" stamped across a whole drainage tells you almost nothing about any single stream in it.

These were bred here in Eugene, Oregon. Not wild-caught. This fish still reaches the hobby mostly as wild imports, and it doesn't have to.

1. Luiza-Andrade, A. et al. Deforestation impacts on environmental conditions of headwater streams and Ephemeroptera (Insecta) diversity in Southwestern Amazonia. Limnology 27, 293-304 (2026).