Can Altum Angel and Dusky Millions Fish Live Together?
Altum Angel and Dusky Millions Fish are not recommended as tank mates due to no temperature overlap and conflicting pH requirements and incompatible hardness ranges. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.
At a Glance
Can your tank handle Altum Angel and Dusky Millions Fish?
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.
Behaviour & Temperament
Altum Angel is a moderately assertive species (5/10), while Dusky Millions Fish is peaceful (2/10). This modest difference means Altum Angel may occasionally assert dominance over Dusky Millions Fish.
Altum Angel and Dusky Millions Fish 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: Hyperactive swimmers can stress shy, slow-moving species through constant motion.
Water Parameters
There is no temperature overlap between Altum Angel (27–32°C) and Dusky Millions Fish (16–24°C). This fundamental mismatch makes long-term cohabitation impractical.
The pH requirements of Altum Angel (4.5–6.5) and Dusky Millions Fish (7–8) do not overlap, making it impossible to satisfy both species simultaneously.
Hardness requirements are incompatible: Altum Angel needs 1–5 dGH while Dusky Millions Fish requires 8–20 dGH.
Tank Setup
To house Altum Angel and Dusky Millions Fish together, plan for an aquarium of at least 400 litres with a minimum length of 120 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: Sand (Sifters), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Plants - Floating, Plants - Densely covered, Established Algae (Otocinclus). Meeting these requirements will help both species thrive.
Both species do well with low (still water) water movement, so a standard filtration setup rated for the tank volume should suffice.
Why This Pairing Usually Fails in Practice
Altum Angel and Dusky Millions Fish 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 Altum Angel and Dusky Millions Fish.
Frequently Asked Questions
Can Altum Angel and Dusky Millions Fish live together?
No. This combination is not recommended. Key incompatibilities — such as non-overlapping temperature ranges — make cohabitation unsafe.
What size tank do Altum Angel and Dusky Millions Fish need?
A minimum of 400 litres (tank length at least 120 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 Altum Angel and Dusky Millions Fish together?
Unfortunately, there is no temperature range that satisfies both species. Altum Angel requires 27–32°C, while Dusky Millions Fish needs 16–24°C.
Are Altum Angel or Dusky Millions Fish aggressive?
Altum Angel is moderately assertive (5/10) and Dusky Millions Fish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.
What pH do Altum Angel and Dusky Millions Fish need?
Their pH requirements do not overlap. Altum Angel prefers 4.5–6.5, while Dusky Millions Fish needs 7–8. This makes them incompatible in the same water chemistry.
Will Dusky Millions Fish nip Altum Angel's fins?
Dusky Millions Fish is a known fin nipper. If Altum Angel has long or flowing fins, there is a real risk of fin damage. Keeping Dusky Millions Fish in a larger group can help redirect nipping behaviour toward conspecifics.
How do I manage Altum Angel's territorial behaviour?
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Altum Angel 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.
Shared setup supplies
We may earn from qualifying purchases
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
Related Comparisons
Altum Angel & Aequidens diadema (Diadem Cichlid)
·
Altum Angel & Aequidens sp. Atabapo
·
Altum Angel & Apistogramma Broad-banded
·
Altum Angel & Apistogramma macmasteri
·
Altum Angel & Apistogramma Mamoré
·
Altum Angel & Apistogramma Mouthbrooder (Maulbrüter)
·
Dusky Millions Fish & Balloon Molly
·
Dusky Millions Fish & Guppy
·
Dusky Millions Fish & Least Killifish (Heterandria)
·
Dusky Millions Fish & Molly (Sailfin/Black/Dalmatian)
·
Dusky Millions Fish & Platy
·
Dusky Millions Fish & Sailfin Molly
·