Blackline Rasbora

The Blackline Rasbora (Rasbora borapetensis) is a freshwater schooling fish valued for a streamlined silver body with a clear dark lateral stripe and metallic highlights. Native to Southeast Asia (Mekong basin), this species is popular in planted community aquariums because it combines visual impact with manageable care requirements. It offers classic schooling behavior for larger community and river-style aquariums.

Appearance and Coloration

Blackline Rasbora is known for clean pattern definition and color response that improves under stable water quality, varied feeding, and proper group size. In mature planted aquariums, the body pattern reads clearly even during fast schooling movement.

Size and Lifespan

• Adult size: 10 cm (3.9 inches)
• Typical lifespan: 5-7 years with stable parameters and quality diet

Ideal Aquarium Setup

This species performs best in a biologically mature aquarium that prioritizes oxygenation and stable chemistry.

• Tank size: 30 gallons (115 L)
• Temperature: 22-26 C (72-79 F)
• pH: 6.5-7.5
• Aquascape direction: long swimming lanes with planted margins and moderate current
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Behavior and Temperament

Blackline Rasbora is an active but non-aggressive open-water schooler that uses the full tank length. Keep groups of at least 8+ individuals so hierarchy and movement are distributed naturally. Good companion options include similarly peaceful mid-sized tetras, danios, rainbowfish, and bottom community fish.

Diet and Feeding

Blackline Rasbora is classified here as Omnivore. Build a varied schedule with high-quality staple foods, plus frozen or live options several times per week. A rotating diet supports immunity, activity, and stronger display color.

Breeding Notes

Most cyprinids in this group are egg scatterers. Conditioning with diverse foods and offering fine-leaved plants or spawning media can improve egg survival. If breeding is the goal, move adults after spawning to reduce egg predation.

Why Keep Blackline Rasbora in a Planted Aquarium?

Blackline Rasbora provides movement, contrast, and schooling structure that helps a layout feel alive without overpowering the design. For aquascaping-focused community tanks, it is a practical and visually rewarding choice.