Arianae tetra

Where they come from

Arianae tetras are South American characins from quiet forest streams and backwaters. Picture leaf-litter on the bottom, tea-colored water, and dappled light from overhanging trees. They are used to soft, slightly acidic water with very little mineral content.

Setting up their tank

They are small, but they like room to school. A 20-long works for a group, though 29 gallons gives you space for plants and tankmates. Use a tight lid. They jump, especially the first week.

• Group size: 10-12+ feels right. In smaller groups they get skittish and may nip more.
• Layout: Dark sand or fine gravel, driftwood, and leaf litter (catappa, oak) for cover. Add fine plants or moss for security.
• Light: Keep it on the dimmer side. Floating plants help them relax.
• Filtration and flow: Gentle to moderate. A small canister or a well-baffled HOB is fine. They appreciate clean, well-oxygenated water without a hurricane current.
• Water targets: 75-81 F (24-27 C), pH 5.5-7.0, GH 1-8 dGH, KH low. Aim for stable, not swingy.
• Maintenance: Weekly 30-40% water changes. These fish show stress fast if nitrates creep up.

What to feed them

Think small and varied. They have tiny mouths and go nuts for moving food. I do two small meals a day most of the time, with a light day once a week.

• Live or frozen: baby brine shrimp, daphnia, cyclops, finely chopped bloodworms (occasional).
• Dry foods: high-quality micro pellets, crushed flakes, and a spirulina-based option for balance.
• Treats: moina, grindal worms, vinegar eels for conditioning.

How they behave and who they get along with

Peaceful, active midwater schoolers. In a big enough group they display to each other and hold loose formations. If you only keep a handful, they get nippy and hide more.

• Great tankmates: other small tetras, rasboras, pencilfish, Corydoras, otos, peaceful dwarf cichlids that mind their own business.
• Caution: long-finned or slow fish (bettas, fancy guppies) can get their fins picked at.
• Skip: large or boisterous fish, most barbs, and anything big enough to eat a tetra.
• Shrimp: adults usually ignore grown shrimp, but tiny shrimplets will get hunted.

Breeding tips

They are open-water egg scatterers that do best with a dedicated setup. Condition the group with live and frozen foods for a week or two. I like a pair or a small group (1-2 males per female) for spawning.

• Tank: 10-15 gallons, bare bottom, a spawning grid or marbles, and a big clump of java moss or spawning mops.
• Water: very soft and acidic helps egg viability (pH 5.5-6.5, GH 1-3), 77-79 F (25-26 C).
• Light: keep it dim. Cover the sides if your room is bright.
• Process: introduce well-fed adults in the evening; they usually spawn at first light.
• After spawning: remove adults right away. Eggs hatch in about 24-36 hours; fry are free-swimming by day 3-5.
• First foods: infusoria/green water for a couple of days, then microworms and newly hatched brine shrimp.

Common problems to watch for

Most issues come from water quality swings and too-small groups. If they start hiding, lose color, or breathe fast at the surface, test the water before anything else.

• Jumping: they spook during maintenance. Keep that lid closed.
• Fin nipping: shows up in undersized groups or bright, barren tanks. Add numbers and cover.
• Ich: pops up after temperature swings. Treat early and raise oxygen.
• Columnaris and other bacterial issues: keep the tank clean, avoid sudden temp jumps, and do not overcrowd.
• Parasites in new stock: thin fish with stringy white poop usually need a dewormer. Quarantine helps catch this.
• Color fade: too much light and no shade. Floating plants and darker substrate fix it fast.