Can Blue Emperor Tetra Live With Cardinal Tetra?
Yes, blue emperor tetras and cardinal tetras make a stunning pair in 20 gallons or larger, with identical care requirements and matching swimming levels.
Why
- Blue emperors grow to 1.5-2 inches and cardinals reach 2 inches, so both species stay well below each other's size threshold.
- Both species school in the middle water column, and the two schools often merge into a single flowing display.
- Temperature overlap of 73-81F suits both species, with 78F being ideal for each.
- Both prefer soft, slightly acidic water in the 6-7 pH range.
- Neither species displays aggression or fin-nipping behavior toward the other.
What could go wrong
Both species are peaceful and neither will harm the other. The main risk is overstocking two schools in a tank that cannot handle the bioload.
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 73-81°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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