Can Amazon Leaf Fish and Knight Goby Live Together?

🔴Not Recommended

Amazon Leaf Fish and Knight Goby 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

Amazon Leaf Fish

Monocirrhus polyacanthus

Knight Goby

Stigmatogobius sadanundio

🐠Family Group
Amazon Leaf Fish
Other
Knight Goby
Gobies & Gudgeons
Temperament
Amazon Leaf Fish
Peaceful (2/10)
Knight Goby
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Amazon Leaf Fish
23–29°C
Knight Goby
20–28°C
pH Range
✗ No overlap
Amazon Leaf Fish
5–6.8
Knight Goby
7–8.5
Hardness (dGH)
✗ No overlap
Amazon Leaf Fish
0–8
Knight Goby
10–30
Water Type
✓ Compatible
Amazon Leaf Fish
Freshwater Only
Knight Goby
Brackish Tolerant
Flow Preference
✓ Compatible
Amazon Leaf Fish
Low
Knight Goby
Moderate
Min Tank Volume
Combined: 90 L
Amazon Leaf Fish
75 L
Knight Goby
75 L
Swimming Level
Shared: 1 zone
Amazon Leaf Fish
MiddleTop
Knight Goby
MiddleBottom
🏷️Behavior Tags
Amazon Leaf Fish
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorShy / Slow Moving (Easily Stressed)Nocturnal
Knight Goby
Fin NipperShrimp EaterFry PredatorTerritorial (Defends specific area)Digger (Disturbs Substrate)Aggressive to same species/look-alikes

Behaviour & Temperament

Amazon Leaf Fish is a peaceful species (2/10), while Knight Goby is moderately assertive (6/10). This notable difference means Knight Goby may occasionally assert dominance over Amazon Leaf Fish.

Amazon Leaf Fish and Knight Goby 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.

Worth noting: Amazon Leaf Fish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

Water Parameters

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Amazon Leaf Fish (5–6.8) and Knight Goby (7–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Amazon Leaf Fish needs 0–8 dGH while Knight Goby requires 10–30 dGH.

Tank Setup

To house Amazon Leaf Fish and Knight Goby together, plan for an aquarium of at least 90 litres with a minimum length of 60 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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: Leaf Litter/Blackwater, Plants - Densely covered, Driftwood (Digestion/Hiding), Plants - Floating, Sand (Sifters), Shells (Breeding/Hiding). 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.

Frequently Asked Questions

Can Amazon Leaf Fish and Knight Goby live together?

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

What size tank do Amazon Leaf Fish and Knight Goby need?

A minimum of 90 litres (tank length at least 60 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 Amazon Leaf Fish and Knight Goby together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Amazon Leaf Fish or Knight Goby aggressive?

Amazon Leaf Fish is peaceful (2/10) and Knight Goby 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 Amazon Leaf Fish and Knight Goby need?

Their pH requirements do not overlap. Amazon Leaf Fish prefers 5–6.8, while Knight Goby needs 7–8.5. This makes them incompatible in the same water chemistry.

Will Knight Goby nip Amazon Leaf Fish's fins?

Knight Goby is a known fin nipper. If Amazon Leaf Fish has long or flowing fins, there is a real risk of fin damage. Keeping Knight Goby in a larger group can help redirect nipping behaviour toward conspecifics.

How do I manage Knight Goby's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Knight Goby 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.

Does Amazon Leaf Fish being nocturnal affect compatibility?

Amazon Leaf Fish is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Amazon Leaf Fish during evening hours.


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