Compatibility Overview
Lemon Tetra and Swordtail are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Lemon Tetra | Swordtail | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 65–80°F | ✅ 72–80°F |
| pH Range | 6.0–7.5 | 7.0–8.3 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 1.6 in | 5 in | ⚠️ 3.1× difference |
| Min. Group | 6+ | 3+ | See below |
| Min. Tank Size | 75 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Lemon Tetra — Aquarium species
The Lemon Tetra is a vibrant, peaceful addition to freshwater tanks. Known for its striking yellow and red colors, it is well-suited for community tanks. They are active swimmers and thrive in groups. Maintaining stable water conditions is key to their health.
Swordtail — Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Frequently Asked Questions
Can Lemon Tetra live with Swordtail?
Generally not recommended. Lemon Tetra and Swordtail are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Lemon Tetra and Swordtail together?
A minimum of 75 gallons is recommended for keeping Lemon Tetra and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Lemon Tetra and Swordtail?
72–80°F
Is a Lemon Tetra aggressive toward a Swordtail?
Lemon Tetra is aggressive and Swordtail is peaceful. The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 80/100 |
| Ph | 38/100 |
| Temperament | 30/100 |
| Adult Size | 38/100 |
| Swim Zone | 68/100 |
| Social Needs | 85/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 75 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 125 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 150 gal | Best when keeping larger schools or reducing territorial pressure. |