Can Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye Live Together?

🔴Not Recommended

Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye are not recommended as tank mates due to incompatible water types. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Figure 8 Puffer (Brackish)

Dichotomyctere ocellatus

Gertrude's Spotted Blue-eye

Pseudomugil gertrudae

🐠Family Group
Figure 8 Puffer (Brackish)
Puffers
Gertrude's Spotted Blue-eye
Rainbowfish
Temperament
Figure 8 Puffer (Brackish)
Aggressive (8/10)
Gertrude's Spotted Blue-eye
Peaceful (2/10)
Temperature
✓ Compatible
Figure 8 Puffer (Brackish)
24–28°C
Gertrude's Spotted Blue-eye
21–28°C
pH Range
✓ Compatible
Figure 8 Puffer (Brackish)
7.5–8.5
Gertrude's Spotted Blue-eye
6–7.5
Hardness (dGH)
✓ Compatible
Figure 8 Puffer (Brackish)
10–25
Gertrude's Spotted Blue-eye
5–15
Water Type
✗ No overlap
Figure 8 Puffer (Brackish)
Brackish Required
Gertrude's Spotted Blue-eye
Freshwater Only
Flow Preference
✓ Compatible
Figure 8 Puffer (Brackish)
Moderate
Gertrude's Spotted Blue-eye
Moderate
Min Tank Volume
Combined: 72 L
Figure 8 Puffer (Brackish)
60 L
Gertrude's Spotted Blue-eye
38 L
Swimming Level
Shared: 1 zone
Figure 8 Puffer (Brackish)
MiddleBottom
Gertrude's Spotted Blue-eye
TopMiddle
🏷️Behavior Tags
Figure 8 Puffer (Brackish)
Snail EaterShrimp EaterFin NipperGenerally AggressiveTerritorial (Defends specific area)Hyperactive / Fast Swimmer
Gertrude's Spotted Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Behaviour & Temperament

Figure 8 Puffer (Brackish) is a semi-aggressive species (8/10), while Gertrude's Spotted Blue-eye is peaceful (2/10). This notable difference means Figure 8 Puffer (Brackish) may occasionally assert dominance over Gertrude's Spotted Blue-eye.

Large aggression gap (6 points) between Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye increases stress risk for the more peaceful fish.

Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye 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.

Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.

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 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 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 10–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye together, plan for an aquarium of at least 72 litres with a minimum length of 60 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: Sand (Sifters), Shells (Breeding/Hiding), Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

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.

Diet & Feeding

Feeding time deserves special attention with this pairing. Figure 8 Puffer (Brackish) is a known shrimp eater and may prey on small invertebrates or nano fish like Gertrude's Spotted Blue-eye.

Frequently Asked Questions

Can Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye need?

A minimum of 72 litres (tank length at least 60 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 Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Figure 8 Puffer (Brackish) or Gertrude's Spotted Blue-eye aggressive?

Figure 8 Puffer (Brackish) is semi-aggressive (8/10) and Gertrude's Spotted Blue-eye is peaceful (2/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Figure 8 Puffer (Brackish) and Gertrude's Spotted Blue-eye need?

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

Will Figure 8 Puffer (Brackish) nip Gertrude's Spotted Blue-eye's fins?

Figure 8 Puffer (Brackish) is a known fin nipper. If Gertrude's Spotted Blue-eye has long or flowing fins, there is a real risk of fin damage. Keeping Figure 8 Puffer (Brackish) in a larger group can help redirect nipping behaviour toward conspecifics.

How do I manage Figure 8 Puffer (Brackish)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Figure 8 Puffer (Brackish) 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.


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