Can Figure 8 Puffer (Brackish) and Penguin Tetra Live Together?

🔴Not Recommended

Figure 8 Puffer (Brackish) and Penguin Tetra 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

Penguin Tetra

Thayeria boehlkei

🐠Family Group
Figure 8 Puffer (Brackish)
Puffers
Penguin Tetra
Characins
Temperament
Figure 8 Puffer (Brackish)
Aggressive (8/10)
Penguin Tetra
Peaceful (2/10)
Temperature
✓ Compatible
Figure 8 Puffer (Brackish)
24–28°C
Penguin Tetra
22–28°C
pH Range
✓ Compatible
Figure 8 Puffer (Brackish)
7.5–8.5
Penguin Tetra
5.5–7.5
Hardness (dGH)
✓ Compatible
Figure 8 Puffer (Brackish)
10–25
Penguin Tetra
2–15
Water Type
✗ No overlap
Figure 8 Puffer (Brackish)
Brackish Required
Penguin Tetra
Freshwater Only
Flow Preference
✓ Compatible
Figure 8 Puffer (Brackish)
Moderate
Penguin Tetra
Moderate
Min Tank Volume
Combined: 90 L
Figure 8 Puffer (Brackish)
60 L
Penguin Tetra
75 L
Swimming Level
Shared: 1 zone
Figure 8 Puffer (Brackish)
MiddleBottom
Penguin Tetra
TopMiddle
🏷️Behavior Tags
Figure 8 Puffer (Brackish)
Snail EaterShrimp EaterFin NipperGenerally AggressiveTerritorial (Defends specific area)Hyperactive / Fast Swimmer
Penguin Tetra
Hyperactive / Fast SwimmerJumper (Lid Required)Fin Nipper

Behaviour & Temperament

Figure 8 Puffer (Brackish) is a semi-aggressive species (8/10), while Penguin Tetra is peaceful (2/10). This notable difference means Figure 8 Puffer (Brackish) may occasionally assert dominance over Penguin Tetra.

Large aggression gap (6 points) between Figure 8 Puffer (Brackish) and Penguin Tetra increases stress risk for the more peaceful fish.

Figure 8 Puffer (Brackish) and Penguin Tetra 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.

Worth noting: Penguin Tetra 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 Penguin Tetra together, plan for an aquarium of at least 90 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. 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.

Frequently Asked Questions

Can Figure 8 Puffer (Brackish) and Penguin Tetra 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 Penguin Tetra need?

A minimum of 90 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 Penguin Tetra 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 Penguin Tetra aggressive?

Figure 8 Puffer (Brackish) is semi-aggressive (8/10) and Penguin Tetra 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 Penguin Tetra 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 Penguin Tetra's fins?

Figure 8 Puffer (Brackish) is a known fin nipper. If Penguin Tetra 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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