Mosaic Guppy (Poecilia reticulata):

Species Care Sheet

The Mosaic Guppy is one of the most visually spectacular varieties of the common guppy. Characterised by a distinctive, intricate “mosaic” or calico-like pattern on its oversized caudal (tail) and dorsal fins, this fish is a staple of the tropical hobby.

While they are often recommended for beginners due to their hardy nature, the vibrant colours and diverse patterns of the Mosaic strain make them equally popular with advanced hobbyists and competitive breeders.

Species Overview

Appearance and Variations

The “Mosaic” trait refers to the irregular, blotchy, or “tessellated” pattern on the fins, which often contrasts sharply against a solid-coloured body. Common variations include:

• Red Mosaic: Deep crimson patterns often paired with a dark or platinum body.

• Blue/Green Mosaic: Shimmering metallic hues that shift in the light.

• Purple/Black Mosaic: High-contrast patterns that are particularly striking in planted aquaria.

Aquarium Requirements

Guppies are adaptable, but to maintain the integrity of their flowing fins and bright colouration, a well-maintained environment is essential.

• Minimum Tank Size: 40–60 litres is ideal for a small group.

• Substrate: Any aquarium-safe substrate; they look particularly vibrant against dark sand or gravel.

• Decor: Use plenty of live plants (such as Guppy Grass, Java Moss, or Hornwort). These provide hiding places for fry and grazing surfaces for the adults.

• Filtration: A gentle-to-moderate flow is best. Very strong currents can “toss” the males around due to their large, sail-like fins.

Water Parameters

Unlike many South American fish, Guppies generally prefer slightly harder, alkaline water.

• Temperature: 22°C – 28°C (24°C–25°C is the “sweet spot” for longevity).

• pH: 7.0 – 8.2

• Hardness: Medium to Hard (10–25°dGH).

• Maintenance: Weekly 10–20% water changes to keep nitrate levels low and prevent “fin rot,” which can plague fancy-finned varieties.

Dietary Needs

Mosaic Guppies are omnivores with a high metabolism. They require a varied diet to support their energy levels and pigment production.

• Primary Diet: A high-quality flake or micro-granule such as NT Labs Probiotic Tropical. The probiotic content helps them process nutrients efficiently, leading to better growth and less waste.

• Vegetable Matter: They naturally graze on algae; providing NT Labs Algae Wafers (broken into small pieces) or spirulina flakes is highly beneficial.

• Treats: Live or frozen daphnia and bloodworm will significantly improve their vibrancy and breeding success.

Behaviour & Compatibility

Guppies are classic community fish. They are active swimmers that spend most of their time in the top and middle layers of the aquarium.

• Ideal Tankmates: Other peaceful species like Mollies, Platies, Neon Tetras, and Corydoras.

• Social Ratio: Always aim for a ratio of two females to every one male. This prevents the males from over-harassing a single female, which can lead to stress and illness.

• Avoid: “Fin-nipping” species such as Tiger Barbs or certain Serpae Tetras, as they will quickly shred the Mosaic Guppy’s delicate tail.

Breeding

Guppies are “livebearers,” meaning the females give birth to fully formed, free-swimming fry rather than laying eggs.

• Gestation: Approximately 28 days.

• Fry Care: If you wish to save the fry, provide dense “spawning mops” or floating plants like Salvinia. Alternatively, use a separate breeding tank.

• Feeding Fry: Newborn fry can eat crushed NT Labs Probiotic Tropical granules or specialised liquid fry food.

Top Tip: To keep your Mosaic strain looking its best, avoid mixing them with other guppy varieties (like Snakeskins or Tuxedos), as the offspring will eventually revert to a “wild-type” look with less distinct patterning.

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