Guides

Freshwater

238 articles · All guides

Malabar Danio (Devario malabaricus)

Western Ghats giants to 15 cm. A 120 cm cool, fast tank or a different species — shop juveniles outgrow “danio” assumptions.

Freshwater

Rose Danio (Danio roseus)

Hill-stream pink and two blue lines. Turn the heater down, stretch the tank, seal the lid, and feed in the current.

Freshwater

Hikari Danio (Danio tinwini)

Tiny spotted gold-ring danios from the upper Irrawaddy. Cooler water, a long box, and enough males that sparring stays theatre.

Freshwater

Orange-finned Danio (Danio kyathit)

Myanmar stream danios with orange paddles. Length, current, a lid, and no zebra hybrids — not a still tetra community fish.

Freshwater

Sun Tetra (Hyphessobrycon heliacus)

A 2002 Tapajós species whose males grow filamentous fins. Soft, slow, species-focused tanks — or shredded gold splinters.

Freshwater

Ornate Tetra (Hyphessobrycon bentosi)

Deep-bodied Amazon tetras with white-tipped fins. Warm, planted schools; males flare, and nippers destroy the reason you bought them.

Freshwater

Dwarf Pencilfish (Nannostomus marginatus)

A 3 cm lebiasinid with three stripes, a pinhead mouth, and a need for still, stained water — not a tetra and not a danio.

Freshwater

Yellow Tail Congo Tetra (Alestopetersius caudalis)

An African alestid from the Congo, not a South American tetra. Gold-yellow tails need length, tannins, and a large shy school.

Freshwater

Cochu's Blue Tetra (Boehlkea fredcochui)

Peru’s steel-blue schooler. Colour is a crowd effect; small groups go grey and start nipping long fins.

Freshwater

Common Hatchetfish (Gasteropelecus sternicla)

Chrome river hatchets that need a sealed top and a long surface runway. Larger and hardier than marbles, still dedicated jumpers.

Freshwater

Marbled Hatchetfish (Carnegiella strigata)

A 4 cm Amazon glider that lives in the surface film. Tight lid, floating food, soft blackwater, and a school — or an empty tank.

Freshwater

Splash Tetra (Copella arnoldi)

Eggs glued above the waterline, a male who splashes them for hours, and a lid that must leave humid air — not a normal tetra spawn.

Freshwater

Ulrey's Tetra (Hemigrammus ulreyi)

Three-lined Paraguay basin tetras that get sold as pencilfish. Cooler than Amazon characins, calmer than Buenos Aires tetras.

Freshwater

Costello Tetra (Hemigrammus hyanuary)

Named for Lago Hyanuary, not a person. Green-gold iridescence and a caudal mark — not a Paracheirodon and not a dyed “green neon.”

Freshwater

Garnet Tetra (Hemigrammus pulcher)

Western Amazon tetras whose black rear wedge only reads as a pattern when the school is large and the water is stained.

Freshwater

Yellow Phantom Tetra (Hyphessobrycon roseus)

Guiana Shield gold with a shoulder blotch, not a bleached black phantom. Quiet midwater schools in soft, dim, planted water.

Freshwater

Buenos Aires Tetra (Hyphessobrycon anisitsi)

A La Plata schooler that likes cooler water, eats soft plants, and nips when understocked — not an Amazon neon with a different label.

Freshwater

Mexican Tetra (Astyanax mexicanus)

Eyed river fish and blind cave morphs share a Latin name. Mexican tetra care splits on light, schooling, and whether the animal can even see its food.

Freshwater

Marbled Catfish (Leiarius marmoratus)

Leiarius marmoratus is a marbled sailfin pimelodid that can pass 60 cm — a huge Amazon predator with a high dorsal, not a barred tiger shovelnose…

Freshwater

Barred Sorubim (Pseudoplatystoma fasciatum)

Pseudoplatystoma fasciatum, the barred or tiger shovelnose, is a metre-class Amazon channel predator — a public-aquarium fish, not a living-room…

Freshwater

Duckbill Catfish (Sorubim lima)

Sorubim lima, the duckbill or shovel-nosed catfish, is a 50-centimetre pimelodid that hunts over sand with a spatula snout — a large river predat…

Freshwater

Cetopsis Catfish (Cetopsis coecutiens)

Cetopsis coecutiens, the whale candiru, is a thick-bodied Amazon scavenger-predator that bites chunks from fish — a dangerous river specialist, n…

Freshwater

Otter Catfish (Helogenes marmoratus)

Helogenes marmoratus, the otter catfish, is a small leaf-litter cetopsid that looks like a mottled tadpole — an insectivore of blackwater debris,…

Freshwater

Auchenipterus Catfish (Auchenipterus nuchalis)

Auchenipterus nuchalis is a midwater, nocturnal driftwood-family catfish of Amazon channels — a schooling insect-hunter, not a log-packing Trache…