Black Diamond Corydoras
Black Diamond Corydoras (Corydoras hastatus), also called the Dwarf Corydoras or Tail Spot Pygmy Cory, is the third of the three true dwarf corydoras species. The body is translucent to silvery with a distinctive bold black spot at the base of the caudal fin — the 'black diamond' that gives this fish its common name. Like the Pygmy Corydoras, C. hastatus is a genuine mid-water schooler rather than a strict bottom-dweller.
Feeding & Care Tip: As a mid-water feeder, Hikari Micro Pellets are the ideal daily staple. Sera Vipachips Tropical Wafers crushed fine work as an alternative. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp. Feed small amounts 2–3 times daily.
Native to the upper Amazon basin in Brazil and Bolivia, Corydoras hastatus inhabits slow-moving streams and flooded areas with dense vegetation. In the aquarium, a well-planted setup with soft to medium water, fine sand substrate, and gentle flow replicates its natural environment. It particularly appreciates areas of fine-leaved plants where it can hover and rest.
Keep in groups of at least ten. Like the Pygmy Corydoras, Black Diamond Corydoras form tight mid-water schools that are mesmerizing to watch. They can be kept alongside Pygmy Corydoras — the two species will often school together. Completely peaceful with all non-predatory species.
One of the smallest armored catfish in the hobby. Fine sand substrate and pristine water quality are essential. Do not keep with fish large enough to consume them.
Care & Ideal Parameters
| Difficulty | Easy |
| Temperament | Peaceful — Nano Community |
| Typical Adult Size | 1.0 inch (2.5 cm) |
| Min. Group Size | 10 minimum — groups of 15+ produce spectacular mid-water schooling |
| Ideal Temp | 72–82°F (22–28°C) |
| Ideal pH | 6.0–7.5 |
| Ideal GH | 2–15 dGH |
| Ideal KH | 1–8 dKH |
| Staple Food | Hikari Micro Pellets; Sera Vipachips Tropical Wafers |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Upper Amazon basin, Brazil and Bolivia |
| Notes | Mid-water schooler like Pygmy Corydoras. Bold black caudal spot is the defining feature. One of the smallest catfish in the hobby. Micro Pellets preferred over Sinking Wafers. Will school with C. pygmaeus. |
