Black Ruby Barb
Black Ruby Barb (Pethia nigrofasciata) undergoes one of the most dramatic color transformations available in a barb. Outside breeding condition, males are attractive but unremarkable — pale with dark vertical bars. When competing or spawning, the front of the body floods with deep, vivid ruby-red and the rear turns jet black — a transformation so complete it is almost unbelievable this is the same fish.
Feeding & Care Tip: Hikari Micro Pellets and Sera Vipan Tropical Flakes make excellent daily staples. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Bloodworms or Hikari Vibra Bites to trigger and maintain the vivid breeding coloration. Hikari Frozen or Freeze-Dried Baby Brine Shrimp are an excellent additional treat.
Native to clear, fast-flowing, shaded forest streams of Sri Lanka — the same biodiverse, threatened freshwater environment as the Cherry Barb. IUCN Vulnerable in the wild; all aquarium stock is captive-bred. Prefers slightly soft, slightly acidic to neutral water with good oxygenation.
Keep in groups of at least six, with more females than males to distribute male attention. Males compete constantly when females are present, maintaining their extraordinary breeding coloration almost continuously in a well-kept group. Completely peaceful and suitable for planted community tanks.
Egg-scatterer. Males in full ruby-and-black breeding color are among the most dramatic small barbs available. The transformation from drab to extraordinary takes seconds and is endlessly fascinating to watch.
Care & Ideal Parameters
| Difficulty | Easy |
| Temperament | Peaceful — community |
| Typical Adult Size | 2.5 inches (6.3 cm) |
| Min. Group Size | 6 minimum — more females than males |
| Ideal Temp | 72–79°F (22–26°C) |
| Ideal pH | 6.0–7.5 |
| Ideal GH | 2–12 dGH |
| Ideal KH | 1–6 dKH |
| Staple Food | Hikari Micro Pellets; Sera Vipan Tropical Flakes |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Bloodworms; Hikari Vibra Bites; Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Sri Lanka (captive-bred stock) |
| Notes | IUCN Vulnerable in wild — aquarium stock captive-bred. Dramatic ruby-red and black breeding coloration in males. Completely peaceful. Requires group with females to trigger best color. |
