Can Cupid Cichlid and Regan's Julie Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Cupid Cichlid and Regan's Julie are not recommended as tank mates due to 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

Cupid Cichlid

Biotodoma cupido

Regan's Julie

Julidochromis regani

🐠Family Group
Cupid Cichlid
Cichlids - South American
Regan's Julie
Cichlids - African
Temperament
Cupid Cichlid
Mostly Peaceful (3/10)
Regan's Julie
Aggressive (7/10)
Temperature
✓ Compatible
Cupid Cichlid
24–29°C
Regan's Julie
23–27°C
pH Range
✗ No overlap
Cupid Cichlid
5–7
Regan's Julie
8–9
Hardness (dGH)
✗ No overlap
Cupid Cichlid
1–8
Regan's Julie
10–25
Water Type
✓ Compatible
Cupid Cichlid
Freshwater Only
Regan's Julie
Freshwater Only
Flow Preference
✓ Compatible
Cupid Cichlid
Low
Regan's Julie
Moderate
Min Tank Volume
Combined: 250 L
Cupid Cichlid
250 L
Regan's Julie
110 L
Swimming Level
Shared: 2 zones
Cupid Cichlid
MiddleBottom
Regan's Julie
BottomMiddle
🏷️Behavior Tags
Cupid Cichlid
Digger (Disturbs Substrate)Shy / Slow Moving (Easily Stressed)
Regan's Julie
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorDigger (Disturbs Substrate)
Stocking calculator

Can your tank handle Cupid Cichlid and Regan's Julie?

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.

Cupid Cichlid
Regan's Julie
Test both in my tank

Behaviour & Temperament

Cupid Cichlid is a generally mild-mannered species (3/10), while Regan's Julie is semi-aggressive (7/10). This notable difference means Regan's Julie may occasionally assert dominance over Cupid Cichlid.

Cupid Cichlid and Regan's Julie both frequent the Middle (Open Water) and Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Water Parameters

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Cupid Cichlid (5–7) and Regan's Julie (8–9) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Cupid Cichlid needs 1–8 dGH while Regan's Julie requires 10–25 dGH.

Tank Setup

To house Cupid Cichlid and Regan's Julie together, plan for an aquarium of at least 250 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. 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

Cupid Cichlid and Regan's Julie 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 Cupid Cichlid and Regan's Julie.

Show 1 more tank size

Frequently Asked Questions

Can Cupid Cichlid and Regan's Julie live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Cupid Cichlid and Regan's Julie need?

A minimum of 250 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 Cupid Cichlid and Regan's Julie together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Cupid Cichlid or Regan's Julie aggressive?

Cupid Cichlid is generally mild-mannered (3/10) and Regan's Julie is semi-aggressive (7/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Cupid Cichlid and Regan's Julie need?

Their pH requirements do not overlap. Cupid Cichlid prefers 5–7, while Regan's Julie needs 8–9. This makes them incompatible in the same water chemistry.

How do I manage Regan's Julie's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Regan's Julie 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.

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?
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