Can Penguin Tetra and Silver Hatchetfish Live Together?

Possible with Caution

Keeping Penguin Tetra and Silver Hatchetfish together is possible but requires caution due to potential behavioral clashes. Provide a spacious tank of at least 75 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Penguin Tetra

Thayeria boehlkei

Silver Hatchetfish

Gasteropelecus sternicla

🐟Family Group
Penguin Tetra
Characins
Silver Hatchetfish
Characins
Temperament
Penguin Tetra
Peaceful (2/10)
Silver Hatchetfish
Peaceful (1/10)
Temperature
✓ Compatible
Penguin Tetra
22–28°C
Silver Hatchetfish
23–28°C
pH Range
✓ Compatible
Penguin Tetra
5.5–7.5
Silver Hatchetfish
6–7.5
Hardness (dGH)
✓ Compatible
Penguin Tetra
2–15
Silver Hatchetfish
2–12
Water Type
✓ Compatible
Penguin Tetra
Freshwater Only
Silver Hatchetfish
Freshwater Only
Flow Preference
✓ Compatible
Penguin Tetra
Moderate
Silver Hatchetfish
Moderate
Min Tank Volume
Combined: 75 L
Penguin Tetra
75 L
Silver Hatchetfish
75 L
Swimming Level
Shared: 1 zone
Penguin Tetra
TopMiddle
Silver Hatchetfish
Top
🏷️Behavior Tags
Penguin Tetra
Hyperactive / Fast SwimmerJumper (Lid Required)Fin Nipper
Silver Hatchetfish
Jumper (Lid Required)Shy / Slow Moving (Easily Stressed)Hyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Penguin Tetra and Silver Hatchetfish?

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.

Penguin Tetra
Silver Hatchetfish
Test both in my tank

Behaviour & Temperament

Penguin Tetra is a peaceful species (2/10), while Silver Hatchetfish is peaceful (1/10). This modest difference means Penguin Tetra may occasionally assert dominance over Silver Hatchetfish.

Penguin Tetra and Silver Hatchetfish both frequent the Top (Surface) 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: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Penguin Tetra is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

Water Parameters

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°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 2–12 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Penguin Tetra and Silver Hatchetfish together, plan for an aquarium of at least 75 litres with a minimum length of 60 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Penguin Tetra and Silver Hatchetfish.

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Frequently Asked Questions

Can Penguin Tetra and Silver Hatchetfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 75 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Penguin Tetra and Silver Hatchetfish need?

A minimum of 75 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 Penguin Tetra and Silver Hatchetfish together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Penguin Tetra or Silver Hatchetfish aggressive?

Penguin Tetra is peaceful (2/10) and Silver Hatchetfish is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Penguin Tetra and Silver Hatchetfish 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.

Will Penguin Tetra nip Silver Hatchetfish's fins?

Penguin Tetra is a known fin nipper. If Silver Hatchetfish has long or flowing fins, there is a real risk of fin damage. Keeping Penguin Tetra in a larger group can help redirect nipping behaviour toward conspecifics.


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