Can Gertrude's Spotted Blue-eye and Red-Tail Catfish Live Together?

🔴Not Recommended

Gertrude's Spotted Blue-eye and Red-Tail Catfish are not recommended as tank mates due to piscivorous fish will prey on nano-sized tank mates.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Gertrude's Spotted Blue-eye

Pseudomugil gertrudae

Red-Tail Catfish

Phractocephalus hemioliopterus

🐠Family Group
Gertrude's Spotted Blue-eye
Rainbowfish
Red-Tail Catfish
Catfish
Temperament
Gertrude's Spotted Blue-eye
Peaceful (2/10)
Red-Tail Catfish
Aggressive (7/10)
Temperature
✓ Compatible
Gertrude's Spotted Blue-eye
21–28°C
Red-Tail Catfish
20–28°C
pH Range
✓ Compatible
Gertrude's Spotted Blue-eye
6–7.5
Red-Tail Catfish
6–7.5
Hardness (dGH)
✓ Compatible
Gertrude's Spotted Blue-eye
5–15
Red-Tail Catfish
3–15
Water Type
✓ Compatible
Gertrude's Spotted Blue-eye
Freshwater Only
Red-Tail Catfish
Freshwater Only
Flow Preference
✓ Compatible
Gertrude's Spotted Blue-eye
Moderate
Red-Tail Catfish
Moderate
Min Tank Volume
Combined: 4560 L
Gertrude's Spotted Blue-eye
38 L
Red-Tail Catfish
3800 L
Swimming Level
✓ Different zones
Gertrude's Spotted Blue-eye
TopMiddle
Red-Tail Catfish
Bottom
🏷️Behavior Tags
Gertrude's Spotted Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Red-Tail Catfish
Piscivore (Eats small/nano fish)Plant DestroyerDigger (Disturbs Substrate)Nocturnal

Behaviour & Temperament

Gertrude's Spotted Blue-eye is a peaceful species (2/10), while Red-Tail Catfish is semi-aggressive (7/10). This notable difference means Red-Tail Catfish may occasionally assert dominance over Gertrude's Spotted Blue-eye.

In terms of spatial distribution, Gertrude's Spotted Blue-eye prefers the Top (Surface) and Middle (Open Water) zones, whereas Red-Tail Catfish occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

There is a critical concern: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

Worth noting: Red-Tail Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Gertrude's Spotted Blue-eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 21°C and 28°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Gertrude's Spotted Blue-eye and Red-Tail Catfish together, plan for an aquarium of at least 4560 litres with a minimum length of 300 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater, Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Red-Tail Catfish is a plant destroyer, which conflicts with Gertrude's Spotted Blue-eye's requirement for live plants. Compromise where possible or prioritise the more critical need.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Gertrude's Spotted Blue-eye and Red-Tail Catfish live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Gertrude's Spotted Blue-eye and Red-Tail Catfish need?

A minimum of 4560 litres (tank length at least 300 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Gertrude's Spotted Blue-eye and Red-Tail Catfish together?

Keep the aquarium between 21°C and 28°C. A target of around 24.5°C sits comfortably within both species' preferred ranges.

Are Gertrude's Spotted Blue-eye or Red-Tail Catfish aggressive?

Gertrude's Spotted Blue-eye is peaceful (2/10) and Red-Tail Catfish is semi-aggressive (7/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Gertrude's Spotted Blue-eye and Red-Tail Catfish need?

Both species overlap in the 6–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Red-Tail Catfish being nocturnal affect compatibility?

Red-Tail Catfish is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Red-Tail Catfish during evening hours.


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