Tank Requirements

• Tank Size: A minimum of 20 gallons (75 liters) for a small group, as they are active swimmers.
• Tank Setup:
  • Provide plenty of open swimming space.
  • Include fine-leaved plants like Java moss, Hornwort, or Vallisneria to mimic their natural habitat and provide hiding spots.
  • Use driftwood or leaf litter to create tannin-stained, slightly acidic water if replicating their native environment.
  • A sandy or fine gravel substrate works well.

Water Parameters

• Temperature: 22-28°C (72-82°F)
• pH: 6.0-7.5 (slightly acidic to neutral)
• Hardness: 5-15 dGH
• Water Flow: Moderate water movement; they prefer clean, well-oxygenated water.
• Filtration: A sponge filter or a gentle HOB filter is ideal to avoid creating too much current.

Regular water changes (25-30% weekly) are crucial to maintain pristine water conditions, as they are sensitive to poor water quality.

Diet

Pseudomugil tenellus are omnivorous and thrive on a varied diet:

• Live/Frozen Foods: Daphnia, brine shrimp, mosquito larvae, and bloodworms.
• Dry Foods: High-quality micro-pellets and crushed flakes.
• Vegetation: Occasionally, supplement with blanched spinach or spirulina-based food.

Feed small amounts twice a day, ensuring the food is small enough for their tiny mouths.

Behavior and Compatibility

• Social Behavior: Peaceful schooling fish. Keep in groups of 6 or more to reduce stress and display natural behaviors.
• Tankmates:
  • Other small, peaceful fish like Celestial Pearl Danios, Neon Tetras, or other small rainbowfish species.
  • Avoid aggressive or fin-nipping species.
  • Consider including bottom-dwellers like Corydoras or Otocinclus for compatibility.

Breeding

• Sexing: Males are more colorful with extended fins, while females are smaller and less vibrant.
• Spawning Conditions:
  • Slightly raise the temperature to 26-28°C (79-82°F).
  • Add spawning mops or fine plants as they scatter eggs.
• Remove adults after spawning to prevent egg predation.
• Eggs hatch in about 7-10 days, and fry can be fed infusoria or finely powdered fry food initially, transitioning to brine shrimp nauplii as they grow.

General Care Tips

• Avoid sudden changes in water parameters to minimize stress.
• Use a tightly fitting lid; they are known jumpers.
• Monitor for diseases, as they are sensitive to parasites and water quality issues.

With proper care, Pseudomugil tenellus can live up to 3-4 years and display vibrant colors and active behavior, making them a delightful addition to a well-maintained aquarium.