Red-Line Tetra (Hyphessobrycon amapaensis)

Red-Line Tetra (Hyphessobrycon amapaensis), also called the Amapa Tetra, is a small peaceful shoaling fish with a clean red lateral stripe over yellow and dark markings. It is a lovely choice for planted aquariums where you want fine movement, colour and calm community behaviour without choosing a large or boisterous tetra.

FishBase records this species from Amapa, Brazil, and gives a maximum length around 3 cm standard length. Seriously Fish places it in the rio Preto and rio Maraca drainage area in Amapa state. In the aquarium that means it should be treated as a small, group-living South American tetra that looks best with plants, subdued areas and stable water.

Quick facts

Best aquarium setup

Use a mature planted aquarium with open swimming space at the front and plant cover toward the back or sides. Darker substrate, wood and floating shade can make the red line stand out, but the tank should still have enough clear water movement for the group to swim together. A calm aquascape also helps newly arrived fish settle without constantly dashing for cover.

Water stability

Do not chase exact pH numbers with sudden chemical changes. Red-Line Tetras generally do best in clean, stable, soft-to-neutral water, so steady maintenance matters more than constant adjustment. If your tap water is much harder than ideal, make any changes slowly and consistently rather than swinging the aquarium between water-change days.

Group size and behaviour

Red-Line Tetras should be bought as a group rather than as one or two fish. A shoal spreads attention, improves confidence and gives the stripe pattern its proper visual effect. In small numbers they can look nervous or washed out, while a settled group is far more active and natural.

Feeding routine

Offer varied small foods. Fine flakes and micro pellets work as staples, while frozen daphnia, cyclops, baby brine shrimp and small bloodworm portions help condition the group. Feed lightly enough that food is eaten quickly; small tetras do better with clean water than with heavy feeding.

Watch the whole group at feeding time. Everyone should get food, not just the boldest fish at the front glass. If smaller fish hang back, spread the food over a wider area or use a mix of floating and slow-sinking particles.

Tank mates

Choose peaceful fish that enjoy similar warm planted conditions. Good companions include small Corydoras, peaceful rasboras, pencilfish, dwarf cichlids with calm temperaments and other non-nippy small tetras. Avoid large predators, tiger-barb style fin nippers and very boisterous fish that will panic the shoal.

Useful comparison links include Cardinal Tetra, Black Neon Tetra, Pygmy Corydoras, Zebra Otocinclus and Brown Kuhli Loach.

Before you order

Acclimation and first week

Keep lights low when the fish arrive and release them into a calm aquarium. They may stay close to cover at first, especially after transport. Offer a small meal once they have settled, then watch for steady shoaling and brightening colour across the first few days.

The first week is mostly about reducing stress. Avoid major rescapes, avoid adding pushy fish at the same time, and let the shoal learn where food appears. A group that eats confidently, swims together and colours up gradually is settling in properly.

Common mistakes to avoid

You might also like

• Cardinal Tetra
• Black Neon Tetra
• Pygmy Corydoras
• Zebra Otocinclus
• Brown Kuhli Loach