Aquarium Care

Pseudomugil gertrudae thrives in planted aquariums with plenty of cover and open swimming space.

Recommended aquarium setup:

• Tank size: 10 gallons minimum (larger preferred for groups)

• Aquascape: Dense plants with open swimming areas

• Substrate: Sand or fine gravel

• Lighting: Moderate to bright lighting

Plants such as:

• Java moss

• Stem plants

• Floating plants

…help create a natural environment and provide spawning sites.

They should always be kept in groups of at least 8–10 individuals, as they are social fish that display best in larger numbers.

Water Parameters

Spotted Blue-Eyes are adaptable but prefer stable conditions.

Recommended parameters:

• Temperature: 74–82°F (23–28°C)

• pH: 6.0–7.5

• Hardness: Soft to moderately hard water (3–12 dGH)

They tolerate a range of conditions but do best in clean, stable water.

Diet

In the wild, Pseudomugil gertrudae feeds on tiny invertebrates.

In the aquarium they prefer:

• Micro pellets

• Crushed flake food

• Frozen foods such as cyclops and baby brine shrimp

• Live foods like microworms or baby brine shrimp

Because of their small mouths, food size is important.

Behavior & Tank Mates

Spotted Blue-Eyes are peaceful, active schooling fish.

Suitable tank mates include:

• Small rasboras

• Ember tetras

• Corydoras

• Shrimp

Males display constantly, flaring their fins and showing off to females and other males.

They occupy the upper and middle levels of the aquarium.

What Is “Pseudomugil gertrudae IV”?

The label “IV” (often meaning “Import Variant” or simply a supplier code) is not a scientific designation. Instead, it typically refers to:

• A specific imported population

• A line used by breeders or wholesalers

• A way to distinguish between similar-looking shipments

In most cases:

• “IV” fish are simply a distinct population with desirable traits

• They may show more spotting, longer fins, or brighter coloration

• The exact origin is sometimes unclear in the trade

So while it sounds technical, “IV” is essentially a trade name, not a separate species or subspecies.

Key Differences Between Variants

Across the different forms, you may notice:

• Fin length: Some populations have longer, more flowing fins

• Spot density: Varies from light speckling to heavy spotting

• Color intensity: Some are brighter yellow/gold, others more subtle

• Body size/shape: Slight variations depending on location

For aquarists, choosing a variant often comes down to aesthetic preference.