Can Black Diamond Cichlid and Licorice Gourami Live Together?

Black Diamond Cichlid is a semi-aggressive species (8/10), while Licorice Gourami is peaceful (2/10). This notable difference means Black Diamond Cichlid may occasionally assert dominance over Licorice Gourami.

Large aggression gap (6 points) between Black Diamond Cichlid and Licorice Gourami increases stress risk for the more peaceful fish.

Black Diamond Cichlid and Licorice Gourami 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.

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

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. Hyperactive swimmers can stress shy, slow-moving species through constant motion.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Black Diamond Cichlid (6.5–8) and Licorice Gourami (3–6) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Black Diamond Cichlid needs 5–20 dGH while Licorice Gourami requires 0–4 dGH.

To house Black Diamond Cichlid and Licorice Gourami together, plan for an aquarium of at least 280 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), Smooth Gravel (Sensitive Barbels), Leaf Litter/Blackwater, Plants - Densely covered, Plants - Floating. 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.

Black Diamond Cichlid and Licorice Gourami 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.