Paradise Threadfin

Iriatherina werneri

Paradise Threadfin (Iriatherina werneri) — Varies care, Peaceful, under Other. Minimum tank in the app: 75 US gal min; aim for 75–82°F and pH 6.5–7.5. The Paradise Threadfin is ideal for aquarists looking to introduce a visually striking species with unique swimming patterns.

Paradise Threadfin (Iriatherina werneri) in a planted freshwater aquarium
Care levelVaries
TemperamentPeaceful
Min tank size75 US gal min
pH range6.5–7.5
Temperature75–82°F
Max size9.8 in (25.0 cm)
Captive lifespan5–8 years
SchoolingNo

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

Australia

  • Australia & Oceania

Regional colours match the stocking calculator’s origin map.

Paradise Threadfin Tank Setup

Create a spacious layout with ample mid-water swimming room, complemented by strategic cover such as plants and driftwood. Moderate water flow suits their swimming style, and a soft substrate can enhance comfort. Lighting should be bright but not harsh, allowing the fish to exhibit natural behaviour without undue stress.

What Do Paradise Threadfins Eat?

They are omnivorous and tend to feed at a moderate pace, which can create competition if housed with faster eaters. Ensure a varied diet to maintain health and enhance coloration, incorporating both flakes and live/frozen foods for optimal nutrition.

Paradise Threadfin Tank Mates

Ideal companions include larger community fish that can hold their own, such as certain cichlids or robust barbs. Avoid overly small or timid species, as they may become targets for aggression. Intraspecies, they generally coexist peacefully unless space is limited, at which point territorial disputes may arise.

Are Paradise Threadfins Good for Beginners?

Care demand varies with setup and individual fish; use the numbers above as your baseline. Aquarists often underestimate the required tank size and filtration needs, leading to poor water quality and increased aggression. neglecting to provide adequate cover can exacerbate territorial behaviour, resulting in stress and potential injury among tank mates.

Building a community? Run the full list through the stocking calculator before you add anything else.

Log tests and reminders in App-aquatic—free, same data you see here.