Can Aequidens diadema (Diadem Cichlid) and American Grass Shrimp Live Together?

Aequidens diadema (Diadem Cichlid) is a moderately assertive species (6/10), while American Grass Shrimp is peaceful (1/10). This notable difference means Aequidens diadema (Diadem Cichlid) may occasionally assert dominance over American Grass Shrimp.

Aequidens diadema (Diadem Cichlid) and American Grass Shrimp 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.

Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.

Worth noting: American Grass Shrimp is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Aequidens diadema (Diadem Cichlid) and American Grass Shrimp to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

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.

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.

To house Aequidens diadema (Diadem Cichlid) and American Grass Shrimp together, plan for an aquarium of at least 200 litres with a minimum length of 90 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Driftwood (Digestion/Hiding), Plants - Densely covered, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Aequidens diadema (Diadem Cichlid) is a plant destroyer, which conflicts with American Grass Shrimp's requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Feeding time deserves special attention with this pairing. Aequidens diadema (Diadem Cichlid) is a known shrimp eater and may prey on small invertebrates or nano fish like American Grass Shrimp.