What size tank does a Redeye Piranha need?

Redeye Piranha needs a minimum of 125 gallons, with 188 gallons recommended. They are middle swimmers.

Is Redeye Piranha good for beginners?

Redeye Piranha is rated "expert" difficulty (4/5). Best for experienced aquarists.

What fish are compatible with Redeye Piranha?

Redeye Piranha is aggressive. Compatible tank mates include other aggressive fish with similar water parameters (pH 6-7.5, temp 75-82°F). Give adequate territory space.

Redeye Piranha

Serrasalmus rhombeus

Family: Characidae • Origin: Various

Redeye Piranha (Serrasalmus rhombeus) is a aggressive tetra reaching 14 inches. Can be kept singly. Minimum tank: 125 gallons.

Min Tank

125 gal

Max Size

14"

Temperature

75-82°F

6-7.5

Lifespan

15 years

School Size

Solo OK

Swim Level

middle

Hardness

5-15 dGH

aggressiveexpertcarnivore

Is Redeye Piranha Right for Your Tank?

Redeye Piranha is rated "expert" (4/5) — best for experienced aquarists. They have specific requirements that make them challenging for beginners. At 125+ gallons minimum, these are large-tank fish. Make sure you have the space and filtration before committing.

Redeye Piranha is aggressive and best kept alone or with other robust species that can hold their own. Not suitable for peaceful community tanks. They are territorial — provide adequate hiding spots and maintain enough space to reduce aggression. Expected lifespan: 15 years with proper care.

Common Mistakes with Redeye Piranha

✗

Relying on a heater without a thermometer

Redeye Piranha needs 75–82°F. Heaters malfunction or drift over time — always use a separate thermometer to verify. Temperature swings of even 3–4°F can trigger stress and disease, particularly ich.

✗

Putting them in a tank under 125 gallons

Many beginners underestimate tank size needs. Redeye Piranha requires at least 125 gallons — ideally 188. Cramped tanks lead to stunted growth, aggression, and poor water quality.

✗

Housing with peaceful nano fish

Redeye Piranha is aggressive and territorial — small, peaceful species like neon tetras, endlers, or celestial pearl danios will be stressed, bullied, or eaten. Choose tank mates that can hold their own.