Can Northern Mountain Swordtail and Teacup Stingray (Common Freshwater Ray) Live Together?

Northern Mountain Swordtail is a generally mild-mannered species (3/10), while Teacup Stingray (Common Freshwater Ray) is moderately assertive (6/10). This modest difference means Teacup Stingray (Common Freshwater Ray) may occasionally assert dominance over Northern Mountain Swordtail.

In terms of spatial distribution, Northern Mountain Swordtail prefers the Top (Surface) and Middle (Open Water) zones, whereas Teacup Stingray (Common Freshwater Ray) 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.

Worth noting: Northern Mountain Swordtail is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 25°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 8–12 dGH. Regular testing will ensure conditions stay within this range.

To house Northern Mountain Swordtail and Teacup Stingray (Common Freshwater Ray) together, plan for an aquarium of at least 750 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.

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: Plants - Densely covered, Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Both species do well with high (river/stream) water movement, so a standard filtration setup rated for the tank volume should suffice.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Northern Mountain Swordtail and Teacup Stingray (Common Freshwater Ray) need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.