Can Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) 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 Terror (Festa's Cichlid)

Mesoheros festae

🐠Family Group
Gertrude's Spotted Blue-eye
Rainbowfish
Red Terror (Festa's Cichlid)
Cichlids - South American
Temperament
Gertrude's Spotted Blue-eye
Peaceful (2/10)
Red Terror (Festa's Cichlid)
Highly Aggressive (10/10)
Temperature
✓ Compatible
Gertrude's Spotted Blue-eye
21–28°C
Red Terror (Festa's Cichlid)
25–29°C
pH Range
✓ Compatible
Gertrude's Spotted Blue-eye
6–7.5
Red Terror (Festa's Cichlid)
6.5–8
Hardness (dGH)
✓ Compatible
Gertrude's Spotted Blue-eye
5–15
Red Terror (Festa's Cichlid)
4–18
Water Type
✓ Compatible
Gertrude's Spotted Blue-eye
Freshwater Only
Red Terror (Festa's Cichlid)
Freshwater Only
Flow Preference
✓ Compatible
Gertrude's Spotted Blue-eye
Moderate
Red Terror (Festa's Cichlid)
Moderate
Min Tank Volume
Combined: 450 L
Gertrude's Spotted Blue-eye
38 L
Red Terror (Festa's Cichlid)
450 L
Swimming Level
Shared: 1 zone
Gertrude's Spotted Blue-eye
TopMiddle
Red Terror (Festa's Cichlid)
MiddleBottom
🏷️Behavior Tags
Gertrude's Spotted Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Red Terror (Festa's Cichlid)
Piscivore (Eats small/nano fish)Generally AggressiveTerritorial (Defends specific area)Digger (Disturbs Substrate)Plant DestroyerAggressive to same species/look-alikes
Stocking calculator

Can your tank handle Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid)?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Gertrude's Spotted Blue-eye
Red Terror (Festa's Cichlid)
Test both in my tank

Behaviour & Temperament

Gertrude's Spotted Blue-eye is a peaceful species (2/10), while Red Terror (Festa's Cichlid) is highly aggressive (10/10). This notable difference means Red Terror (Festa's Cichlid) may occasionally assert dominance over Gertrude's Spotted Blue-eye.

Large aggression gap (8 points) between Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) increases stress risk for the more peaceful fish.

Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) both frequent the Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

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: 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 25°C and 28°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 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.

Tank Setup

To house Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) together, plan for an aquarium of at least 450 litres with a minimum length of 150 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

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), Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Red Terror (Festa's Cichlid) 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.

Why This Pairing Usually Fails in Practice

Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid).

Frequently Asked Questions

Can Gertrude's Spotted Blue-eye and Red Terror (Festa's Cichlid) 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 Terror (Festa's Cichlid) need?

A minimum of 450 litres (tank length at least 150 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 Terror (Festa's Cichlid) together?

Keep the aquarium between 25°C and 28°C. A target of around 26.5°C sits comfortably within both species' preferred ranges.

Are Gertrude's Spotted Blue-eye or Red Terror (Festa's Cichlid) aggressive?

Gertrude's Spotted Blue-eye is peaceful (2/10) and Red Terror (Festa's Cichlid) is highly aggressive (10/10). 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 Terror (Festa's Cichlid) need?

Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

How do I manage Red Terror (Festa's Cichlid)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Red Terror (Festa's Cichlid) space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 4, 2026
Last updated
May 4, 2026
Issues or corrections?
Contact the editorial team

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