Can Cardinal Tetra Live With Rummy Nose Tetra?
Yes, cardinal tetras and rummy nose tetras school together beautifully in 20 gallons or larger, sharing soft acidic water parameters.
Why
- Both species are mid-level schooling tetras from South America, so they occupy the same swimming zone and schooling behavior is complementary.
- Cardinal tetras reach 2 inches and rummy nose tetras reach 2-2.5 inches, close enough in size that they school naturally together without size-based clumping.
- Temperature overlap spans 75-81°F and pH overlap is 5.5-7.0, a narrow but comfortable range for both species.
- Both prefer soft, acidic water from the Rio Negro region, giving them compatible preferences that go beyond mere tolerance.
What could go wrong
A school of 8+ combined tetras makes it harder to track individual fish, so illness in one fish may go unnoticed longer.
Gear for a shared tank
Sized for the 20 gallon minimum this pairing needs. Affiliate links — we earn a small commission if you buy through them.
AquaClear 30 Power Filter
Oversized filtration is what lets you stock two species together without water quality crashing. Rated for a tank slightly larger than the 20 gallon minimum.
Eheim Jager 150W Thermostat Heater
Holds a steady temperature inside the 75-81°F window both species need.
API Freshwater Master Test Kit
Keep ammonia, nitrite, and nitrate in check. Two-species tanks have more bioload and less margin for error than single-species setups.
Related compatibility questions
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