Compatibility Overview
Swordtail and Weather Loach can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 55 gallons), dense planting, and close monitoring are essential.
| Factor | Swordtail | Weather Loach | Verdict |
|---|---|---|---|
| Temperature | 65–80°F | 59–72°F | ✅ 65–72°F |
| pH Range | 7.0–8.3 | 6.5–7.5 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 5 in | 3.9 in | ✅ Similar |
| Min. Group | 3+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Swordtail — Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Weather Loach — Aquarium species
The Weather Loach, also known as the Weather Fish, is a popular addition to freshwater aquariums due to its peaceful nature and intriguing behavior. It has a slender, eel-like body with a translucent appearance and dark spots. These loaches are active and enjoy exploring their tank, making them a moderate activity level fish. They do not school and are gener
Frequently Asked Questions
Can Swordtail live with Weather Loach?
With significant caution and a larger tank. Swordtail and Weather Loach can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 55 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Swordtail and Weather Loach together?
A minimum of 55 gallons is recommended for keeping Swordtail and Weather Loach together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Swordtail and Weather Loach?
65–72°F
Is a Swordtail aggressive toward a Weather Loach?
Swordtail is peaceful and Weather Loach is aggressive. No major aggression issues are expected between these species.
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 | 54/100 |
| Ph | 50/100 |
| Temperament | 30/100 |
| Adult Size | 100/100 |
| Swim Zone | 92/100 |
| Social Needs | 92/100 |
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 | 55 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 75 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 125 gal | Best when keeping larger schools or reducing territorial pressure. |