Can Flyspeck Hardyhead and Murray River Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Ideal Tank Mates

Yes, Flyspeck Hardyhead and Murray River Rainbowfish are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. A minimum tank size of 110 litres is recommended.


At a Glance

Flyspeck Hardyhead

Craterocephalus stercusmuscarum

Murray River Rainbowfish

Melanotaenia fluviatilis

🐠Family Group
Flyspeck Hardyhead
Other
Murray River Rainbowfish
Rainbowfish
Temperament
Flyspeck Hardyhead
Peaceful (1/10)
Murray River Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Flyspeck Hardyhead
22–28°C
Murray River Rainbowfish
20–26°C
pH Range
✓ Compatible
Flyspeck Hardyhead
6–8
Murray River Rainbowfish
6.5–8
Hardness (dGH)
✓ Compatible
Flyspeck Hardyhead
5–15
Murray River Rainbowfish
8–20
Water Type
✓ Compatible
Flyspeck Hardyhead
Freshwater Only
Murray River Rainbowfish
Freshwater Only
Flow Preference
✓ Compatible
Flyspeck Hardyhead
Moderate
Murray River Rainbowfish
Moderate
Min Tank Volume
Combined: 110 L
Flyspeck Hardyhead
75 L
Murray River Rainbowfish
110 L
Swimming Level
Shared: 2 zones
Flyspeck Hardyhead
TopMiddle
Murray River Rainbowfish
TopMiddle
🏷️Behavior Tags
Flyspeck Hardyhead
Hyperactive / Fast SwimmerJumper (Lid Required)
Murray River Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Aggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Flyspeck Hardyhead and Murray River Rainbowfish?

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.

Flyspeck Hardyhead
Murray River Rainbowfish
Test both in my tank

Behaviour & Temperament

Flyspeck Hardyhead is a peaceful species (1/10), while Murray River Rainbowfish is peaceful (2/10). This modest difference means Murray River Rainbowfish may occasionally assert dominance over Flyspeck Hardyhead.

Flyspeck Hardyhead and Murray River Rainbowfish both frequent the Top (Surface) and 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: Flyspeck Hardyhead is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 22°C and 26°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Flyspeck Hardyhead and Murray River Rainbowfish together, plan for an aquarium of at least 110 litres with a minimum length of 90 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, Established Algae (Otocinclus). 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.

Why This Pairing Works in Practice

Flyspeck Hardyhead and Murray River Rainbowfish work best when the tank gives each fish enough room to use its preferred level of the aquarium and enough cover to avoid constant visual contact. The score matters, but the real-world success usually comes from matching their pace, keeping water stable, and resisting the urge to crowd the tank just because the pair looks safe on paper.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Flyspeck Hardyhead and Murray River Rainbowfish.

Show 10 more tank sizes

Frequently Asked Questions

Can Flyspeck Hardyhead and Murray River Rainbowfish live together?

Yes. Flyspeck Hardyhead and Murray River Rainbowfish are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Flyspeck Hardyhead and Murray River Rainbowfish need?

A minimum of 110 litres (tank length at least 90 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 Flyspeck Hardyhead and Murray River Rainbowfish together?

Keep the aquarium between 22°C and 26°C. A target of around 24.0°C sits comfortably within both species' preferred ranges.

Are Flyspeck Hardyhead or Murray River Rainbowfish aggressive?

Flyspeck Hardyhead is peaceful (1/10) and Murray River Rainbowfish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Flyspeck Hardyhead and Murray River Rainbowfish need?

Both species overlap in the 6.5–8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Editorial Review

Guidarium Editorial Desk

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

Last reviewed
May 6, 2026
Last updated
May 6, 2026
Issues or corrections?
Contact the editorial team

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