Compatibility Overview
Otocinclus and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Otocinclus | 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 | peaceful | peaceful | ✅ Compatible |
| Adult Size | 1.5 in | 5 in | ⚠️ 3.3× difference |
| Min. Group | 4+ | 3+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Otocinclus — Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
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 Otocinclus live with Swordtail?
Yes, in a well-planned setup. Otocinclus and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Otocinclus and Swordtail together?
A minimum of 55 gallons is recommended for keeping Otocinclus and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Otocinclus and Swordtail?
72–80°F
Is a Otocinclus aggressive toward a Swordtail?
Otocinclus is peaceful and Swordtail is peaceful. Limited pH overlap (7.0–7.5) — maintain pH carefully within this narrow window.