Can Delicate Blue-Eye and Goldfish (Comet / Common) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Delicate Blue-Eye and Goldfish (Comet / Common) are not recommended as tank mates due to no temperature overlap. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Delicate Blue-Eye

Pseudomugil tenellus

Goldfish (Comet / Common)

Carassius auratus

🐠Family Group
Delicate Blue-Eye
Rainbowfish
Goldfish (Comet / Common)
Goldfish & Koi
Temperament
Delicate Blue-Eye
Peaceful (1/10)
Goldfish (Comet / Common)
Peaceful (1/10)
Temperature
✗ No overlap
Delicate Blue-Eye
25–32°C
Goldfish (Comet / Common)
10–24°C
pH Range
✓ Compatible
Delicate Blue-Eye
5–7.5
Goldfish (Comet / Common)
6.5–8
Hardness (dGH)
✓ Compatible
Delicate Blue-Eye
5–15
Goldfish (Comet / Common)
5–20
Water Type
✓ Compatible
Delicate Blue-Eye
Brackish Tolerant
Goldfish (Comet / Common)
Freshwater Only
Flow Preference
✓ Compatible
Delicate Blue-Eye
Moderate
Goldfish (Comet / Common)
Moderate
Min Tank Volume
Combined: 200 L
Delicate Blue-Eye
60 L
Goldfish (Comet / Common)
200 L
Swimming Level
Shared: 2 zones
Delicate Blue-Eye
TopMiddle
Goldfish (Comet / Common)
TopMiddleBottom
🏷️Behavior Tags
Delicate Blue-Eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Goldfish (Comet / Common)
Plant DestroyerDigger (Disturbs Substrate)Aggressive Eater (Starves shy fish)Hyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Delicate Blue-Eye and Goldfish (Comet / Common)?

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.

Delicate Blue-Eye
Goldfish (Comet / Common)
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Behaviour & Temperament

Both Delicate Blue-Eye and Goldfish (Comet / Common) are peaceful species with an aggression score of 1/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Delicate Blue-Eye and Goldfish (Comet / Common) 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: Delicate Blue-Eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

There is no temperature overlap between Delicate Blue-Eye (25–32°C) and Goldfish (Comet / Common) (10–24°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6.5 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 5–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Delicate Blue-Eye and Goldfish (Comet / Common) together, plan for an aquarium of at least 200 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: Plants - Densely covered, Plants - Floating, Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Goldfish (Comet / Common) is a plant destroyer, which conflicts with Delicate Blue-Eye's requirement for live plants. Compromise where possible or prioritise the more critical need.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Why This Pairing Usually Fails in Practice

Delicate Blue-Eye and Goldfish (Comet / Common) 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 Delicate Blue-Eye and Goldfish (Comet / Common).

Show 5 more tank sizes

Frequently Asked Questions

Can Delicate Blue-Eye and Goldfish (Comet / Common) live together?

No. This combination is not recommended. Key incompatibilities — such as non-overlapping temperature ranges — make cohabitation unsafe.

What size tank do Delicate Blue-Eye and Goldfish (Comet / Common) need?

A minimum of 200 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 Delicate Blue-Eye and Goldfish (Comet / Common) together?

Unfortunately, there is no temperature range that satisfies both species. Delicate Blue-Eye requires 25–32°C, while Goldfish (Comet / Common) needs 10–24°C.

Are Delicate Blue-Eye or Goldfish (Comet / Common) aggressive?

Delicate Blue-Eye is peaceful (1/10) and Goldfish (Comet / Common) is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Delicate Blue-Eye and Goldfish (Comet / Common) need?

Both species overlap in the 6.5–7.5 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 4, 2026
Last updated
May 4, 2026
Issues or corrections?
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