Scarlet Badis
Scarlet Badis (Dario dario) is one of the most breathtakingly beautiful nano fish in the freshwater hobby — and one of the most rewarding to keep well. Males are tiny jewels: deep scarlet-red bodies crossed by vivid blue-iridescent vertical stripes, with bright blue fin markings and a bold black dorsal spot. At under an inch, they carry more visual impact per millimeter than almost any other freshwater fish. Females are considerably plainer — pale and translucent — but essential for keeping males in display condition.
Feeding & Care Tip: Hikari Micro Pellets and Hikari Frozen or Freeze-Dried Baby Brine Shrimp are the daily staples. Supplement with Hikari Frozen or Freeze-Dried Tubifex Worms and Hikari Frozen Daphnia 2–3× per week. For a special treat, newly hatched live baby brine shrimp are an outstanding conditioning food that triggers peak color and breeding behavior. Feed small amounts in a calm tank — Scarlet Badis are slow, deliberate feeders that cannot compete with faster fish at feeding time.
Native to tributary systems draining into the Brahmaputra River in West Bengal and Assam, India — possibly extending into Bhutan. This species inhabits extremely shallow, slow-moving to still, heavily vegetated streams and seasonal pools with sandy substrate and dense aquatic vegetation. In the aquarium, a nano setup of 5–10 gallons with very gentle filtration, dense planting, fine substrate, and tannin additions from Indian almond leaves is ideal. This is not a fish for a busy community tank.
Keep one male per tank, or one male per clearly defined territory in a larger planted setup — males fight fiercely and fatally if they cannot escape each other. One male with two or three females is the most rewarding arrangement: the presence of females keeps males in constant display, showing their most vivid color. Despite their micro-predator status, Dario species can coexist peacefully with carefully chosen tankmates. Small, fast-moving nano rasboras occupy different water zones and move too quickly to be threatened. Planted shrimp tanks also work well — adult shrimp are generally safe, but be aware that Dario species may prey on very small baby shrimp. Avoid any active feeders that will outcompete these slow, deliberate fish for food.
Scarlet Badis are egg-scatterers that spawn among fine-leaved plants or Java moss. The male courts the female with elaborate fin-spreading displays — his coloration intensifies to extraordinary levels during breeding. Eggs are scattered and receive no parental care; in a species-only or lightly stocked planted tank, some fry will survive. The critical feeding challenge with Dario species is their small mouth, slow feeding pace, and preference for moving food. Always feed in a calm aquarium and observe that all fish are actually eating — fast tankmates will steal food before Darios can respond.
Care & Ideal Parameters
| Difficulty | Moderate |
| Temperament | Territorial between males — nano specialist |
| Typical Adult Size | 0.8 inches male / 0.5 inches female |
| Min. Group Size | 1 male with 2–3 females — species-specific or nano planted setup |
| Ideal Temp | 72–79°F (22–26°C) |
| Ideal pH | 6.5–7.5 |
| Ideal GH | 3–12 dGH |
| Ideal KH | 1–6 dKH |
| Staple Food | Hikari Micro Pellets; Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Tubifex Worms; Hikari Frozen Daphnia; Newly hatched live baby brine shrimp (special treat) |
| Origin | Brahmaputra River tributaries, West Bengal and Assam, India |
| Notes | One of the smallest and most beautiful fish in the hobby. Males fight fatally — 1 male per tank. Females are essential for male display. Cannot compete with fast feeders. Newly hatched BBS is the best conditioning food. Nano planted setup strongly recommended. |