Can Cardinal Tetra and Thai Micro Crab Live Together?

Cardinal Tetra is a peaceful species (1/10), while Thai Micro Crab is peaceful (0/10). This modest difference means Cardinal Tetra may occasionally assert dominance over Thai Micro Crab.

In terms of spatial distribution, Cardinal Tetra prefers the Middle (Open Water) zone, whereas Thai Micro Crab occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

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

Worth noting: Thai Micro Crab is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

To improve the chances of a peaceful coexistence in this community tank: 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 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 6–8 dGH. Regular testing will ensure conditions stay within this range.

To house Cardinal Tetra and Thai Micro Crab together, plan for an aquarium of at least 66 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.

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