Can Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) are not recommended as tank mates due to conflicting pH requirements and piscivorous fish will prey on nano-sized tank mates.. 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

Fosso Cichlid (Fossorochromis rostratus)

Fossorochromis rostratus

🐠Family Group
Delicate Blue-Eye
Rainbowfish
Fosso Cichlid (Fossorochromis rostratus)
Cichlids - African
Temperament
Delicate Blue-Eye
Peaceful (1/10)
Fosso Cichlid (Fossorochromis rostratus)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Delicate Blue-Eye
25–32°C
Fosso Cichlid (Fossorochromis rostratus)
24–28°C
pH Range
✗ No overlap
Delicate Blue-Eye
5–7.5
Fosso Cichlid (Fossorochromis rostratus)
7.8–8.6
Hardness (dGH)
✓ Compatible
Delicate Blue-Eye
5–15
Fosso Cichlid (Fossorochromis rostratus)
10–25
Water Type
✓ Compatible
Delicate Blue-Eye
Brackish Tolerant
Fosso Cichlid (Fossorochromis rostratus)
Freshwater Only
Flow Preference
✓ Compatible
Delicate Blue-Eye
Moderate
Fosso Cichlid (Fossorochromis rostratus)
Moderate
Min Tank Volume
Combined: 680 L
Delicate Blue-Eye
60 L
Fosso Cichlid (Fossorochromis rostratus)
680 L
Swimming Level
Shared: 1 zone
Delicate Blue-Eye
TopMiddle
Fosso Cichlid (Fossorochromis rostratus)
BottomMiddle
🏷️Behavior Tags
Delicate Blue-Eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Fosso Cichlid (Fossorochromis rostratus)
Digger (Disturbs Substrate)Territorial (Defends specific area)Hyperactive / Fast SwimmerPiscivore (Eats small/nano fish)
Stocking calculator

Can your tank handle Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus)?

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
Fosso Cichlid (Fossorochromis rostratus)
Test both in my tank

Behaviour & Temperament

Delicate Blue-Eye is a peaceful species (1/10), while Fosso Cichlid (Fossorochromis rostratus) is moderately assertive (6/10). This notable difference means Fosso Cichlid (Fossorochromis rostratus) may occasionally assert dominance over Delicate Blue-Eye.

Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) 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.

There is a critical concern: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

Worth noting: Delicate Blue-Eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 25°C and 28°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

The pH requirements of Delicate Blue-Eye (5–7.5) and Fosso Cichlid (Fossorochromis rostratus) (7.8–8.6) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) together, plan for an aquarium of at least 680 litres with a minimum length of 180 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). 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 Usually Fails in Practice

Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) 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 Fosso Cichlid (Fossorochromis rostratus).

Frequently Asked Questions

Can Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) live together?

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

What size tank do Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) need?

A minimum of 680 litres (tank length at least 180 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 Fosso Cichlid (Fossorochromis rostratus) together?

Keep the aquarium between 25°C and 28°C. A target of around 26.5°C sits comfortably within both species' preferred ranges.

Are Delicate Blue-Eye or Fosso Cichlid (Fossorochromis rostratus) aggressive?

Delicate Blue-Eye is peaceful (1/10) and Fosso Cichlid (Fossorochromis rostratus) is moderately assertive (6/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Delicate Blue-Eye and Fosso Cichlid (Fossorochromis rostratus) need?

Their pH requirements do not overlap. Delicate Blue-Eye prefers 5–7.5, while Fosso Cichlid (Fossorochromis rostratus) needs 7.8–8.6. This makes them incompatible in the same water chemistry.

How do I manage Fosso Cichlid (Fossorochromis rostratus)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Fosso Cichlid (Fossorochromis rostratus) 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?
Contact the editorial team

Related Comparisons

Delicate Blue-Eye & Black-Banded Rainbowfish

·

Ideal Tank Mates
Delicate Blue-Eye: PeacefulBlack-Banded Rainbowfish: Peaceful

Delicate Blue-Eye & Celebes Rainbowfish

·

Ideal Tank Mates
Delicate Blue-Eye: PeacefulCelebes Rainbowfish: Peaceful

Delicate Blue-Eye & Pacific Blue Eye

·

Possible with Caution
Delicate Blue-Eye: PeacefulPacific Blue Eye: Peaceful

Delicate Blue-Eye & Ajamaru Rainbowfish

·

Possible with Caution
Delicate Blue-Eye: PeacefulAjamaru Rainbowfish: Peaceful

Delicate Blue-Eye & Allen's Rainbowfish

·

Ideal Tank Mates
Delicate Blue-Eye: PeacefulAllen's Rainbowfish: Peaceful

Delicate Blue-Eye & Angfa Rainbowfish

·

Ideal Tank Mates
Delicate Blue-Eye: PeacefulAngfa Rainbowfish: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & Afra Cichlid

·

Possible with Caution
Fosso Cichlid (Fossorochromis rostratus): PeacefulAfra Cichlid: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & African Jewel Cichlid

·

Not Recommended
Fosso Cichlid (Fossorochromis rostratus): PeacefulAfrican Jewel Cichlid: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & Altolamprologus Calvus

·

Possible with Caution
Fosso Cichlid (Fossorochromis rostratus): PeacefulAltolamprologus Calvus: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & Altolamprologus Compressiceps

·

Possible with Caution
Fosso Cichlid (Fossorochromis rostratus): PeacefulAltolamprologus Compressiceps: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & Aurora Yellow Mbuna

·

Possible with Caution
Fosso Cichlid (Fossorochromis rostratus): PeacefulAurora Yellow Mbuna: Peaceful

Fosso Cichlid (Fossorochromis rostratus) & Black Diamond Cichlid

·

Possible with Caution
Fosso Cichlid (Fossorochromis rostratus): PeacefulBlack Diamond Cichlid: Peaceful