Peppermint Otocinclus
Peppermint Otocinclus (Rhinotocinclus eppleyi) is a charming and less commonly available species from the upper Amazon. The pale body is decorated with a series of dark spots and blotches arranged along the flanks in a broken, irregular pattern — a softer, more speckled look compared to the crisp stripes of the Zebra Oto. It belongs to the genus Rhinotocinclus, established in 2022 to accommodate several species previously classified as Parotocinclus.
Feeding & Care Tip: Live algae growing on the aquarium glass, plants, and hardscape is the single most important food source for Otocinclus — a tank without established algae growth will not sustain these fish regardless of what supplemental food is offered. Allow biofilm and green algae to develop on surfaces before adding otos, and do not over-clean the aquarium. Supplement with Hikari Mini Algae Wafers placed directly on the glass or substrate, and offer blanched vegetables — zucchini, cucumber, or spinach — 2–3 times per week. Remove uneaten vegetable matter within 24 hours to prevent water quality issues.
Native to upper Amazon tributaries in Peru and surrounding regions, this species inhabits clean, well-oxygenated, slightly acidic water with abundant biofilm and algae-covered surfaces and vegetation. As with all otos, a mature aquarium with established algae growth is essential before introducing this species.
Otocinclus are schooling fish that are markedly more confident, active, and healthy in groups. A lone otocinclus is a stressed otocinclus — it will hide constantly, refuse supplemental food, and decline over time. Keep a minimum of six, and ideally eight or more. In a proper group they are bold, constantly grazing, and frequently seen resting together in clusters on broad plant leaves or the aquarium glass.
Otocinclus are notoriously sensitive during the transition from the wild to captivity — virtually all trade specimens are wild-caught, and the stress of collection and shipping leaves them vulnerable in the first weeks. Slow, careful drip acclimation over at least an hour is strongly recommended. A mature aquarium with established algae growth, stable water parameters, clean water, and good oxygenation gives newly arrived fish the best possible start.
Care & Ideal Parameters
| Difficulty | Moderate |
| Temperament | Peaceful — Community |
| Typical Adult Size | 1.75 inches (4.5 cm) |
| Min. Group Size | 6 minimum — groups of 8+ strongly recommended |
| Ideal Temp | 72–79°F (22–26°C) |
| Ideal pH | 6.0–7.0 |
| Ideal GH | 2–12 dGH |
| Ideal KH | 1–6 dKH |
| Primary Food | Live algae and biofilm (from aquarium surfaces); Hikari Mini Algae Wafers |
| Supplemental Food | Blanched zucchini, cucumber, or spinach — offered 2–3 times per week |
| Origin | Upper Amazon tributaries, Peru |
| Notes | Reclassified from Parotocinclus to Rhinotocinclus in 2022. Spotted and blotched pattern rather than stripes. Wild-caught — drip acclimate carefully. Mature tank with established algae required. Groups of 6+ essential. |
