Phoenix rasbora (Boraras merah)

Phoenix Rasbora (commonly sold as Boraras merah) is a tiny, colorful nano schooling fish that thrives in calm, heavily planted aquariums. It is peaceful and can be shy in small groups, but becomes more active and confident when kept in a larger school. This species is closely associated with slow, tannin-stained blackwater environments, so it appreciates gentle flow and lots of cover. A mature, fully cycled aquarium is important because nano fish are sensitive to ammonia and nitrite spikes. They do best with stable parameters, consistent maintenance, and careful feeding with very small foods. Dense plants, moss, driftwood, and dark substrate help reduce stress and enhance coloration. They are easily outcompeted by larger or fast tankmates, so a peaceful nano community is ideal. When comfortable, a group forms a lively mid-water “feature school” and shows stronger reds/oranges with a darker lateral line. Overall, Phoenix Rasboras are an excellent choice for planted nano or blackwater-style tanks focused on calm micro-species.

Water parameters

Temperature:	73–82°F (23–28°C), stable and warm.
pH:	5.0–7.0 (soft/acidic preferred; stability matters most).
Hardness:	1–8 dGH (soft water preferred).
Other:	Ammonia and nitrites must be 0 ppm at all times; nitrates should be kept low (ideally under ~20 ppm) through regular maintenance, controlled feeding, and stable filtration.
Water changes:	Typically change 20–30% weekly to keep water quality stable. In small tanks or with heavier stocking, smaller changes twice per week (e.g., 15–20% twice weekly) can be even better than one larger change.

Behavior & compatibility

Schooling Behavior: Phoenix rasboras are schooling fish that thrive in groups; larger groups make them bolder and improve shoaling behavior. Phoenix rasbora (Boraras merah) should be kept in groups (minimum 8; ideally 12–15 for best display).
Temperament: Phoenix Rasboras are peaceful, not aggressive, and not typically fin-nippers. They are more likely to be stressed by aggressive or fast tankmates than to cause issues themselves.
Centrepiece: hoenix Rasboras are generally not a single “centerpiece” fish; instead, a larger school becomes the visual feature of the aquarium through group movement and color.
Prolific or Livebearing:They are egg-scatterers and not livebearers. They may spawn occasionally in mature planted tanks, but they are not typically prolific in community setups unless breeding is intentionally supported.
Swimming zone:Phoenix Rasboras primarily occupy the middle to upper water levels and are active mid-water swimmers rather than bottom-dwellers.
Interaction with Plants:Phoenix Rasboras are excellent with live plants and do not damage them. Dense planting provides security and helps stabilize water quality in nano aquariums.

Setup essentials

Lid: A tank cover is preferred because they can jump when startled, and it also reduces evaporation and helps keep temperature stable.
Filter: A filter is necessary. Use a gentle filter (sponge filter is ideal) because strong flow can stress them, and stable biofiltration is critical for nano fish.
Substrate: Dark, fine substrate (sand or planted soil) is preferred. Dark substrate reduces stress, enhances coloration, and pairs well with planted/blackwater layouts; optional leaf litter fits their natural style.
Lighting: Moderate aquarium lighting is preferred—mainly to support live plants and normal viewing. They don’t require intense light; floating plants can help diffuse brightness.
Heater: A heater is preferred and can be necessary if room temperature does not reliably keep the aquarium within 23–28°C. Stability is more important than chasing an exact number.
Air Pump: An air pump is not strictly necessary if the filter provides good surface agitation, but gentle aeration is helpful (preferred) in warm tanks, very still water, or heavily planted setups at night.

Feeding Regimen

Feed 1–2 times per day in small portions. Preferred foods are tiny: micro pellets, crushed flakes, baby brine shrimp, daphnia/cyclops, and microworms. Spread food out so all fish eat, since they are small and can be outcompeted.

Lifespan

With proper care, Phoenix Rasboras typically live about 3–5 years.

Interesting Facts

Phoenix Rasboras often show their best orange-red coloration in darker, heavily planted or blackwater-style tanks with gentle flow. Keeping them in larger groups noticeably improves confidence and display behavior. Because they’re tiny, using micro-foods and distributing food across the tank helps ensure everyone eats.