Fish comparison
Otocinclus (Common) vs Reticulated Hillstream Loach
How the Otocinclus (Common) and Reticulated Hillstream Loach compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Otocinclus (Common) vs Reticulated Hillstream Loach
The Otocinclus (Common) and the Reticulated Hillstream Loach come up together a lot when people are choosing a fish, and they are close enough to weigh side by side. Both are happy somewhere around 20 to 24 °C and pH 6.5 to 7.5, so a single tank can suit either one. Neither is harder than the other to keep, so the choice comes down to look and stocking rather than skill. If tank space is tight, the Otocinclus (Common) needs less room to feel settled; give the Reticulated Hillstream Loach the nod when you have the litres to spare.
Group compatibility overview
Good fit
Workable as-is, only minor advisories to plan around.
1 warning · 1 note
Temperature
- Otocinclus (Common)20–26 °C
- Reticulated Hillstream Loach20–24 °C
pH
- Otocinclus (Common)6–7.5
- Reticulated Hillstream Loach6.5–7.5
Hardness
- Otocinclus (Common)2–10 dGH
- Reticulated Hillstream Loach4–15 dGH
What to plan for
- Otocinclus (Common) schools, stock at least 6You've planned for 1 otocinclus (common). Otocinclus (Common) need a group of at least 6 to feel safe and shoal naturally, below that they're stressed and lose colour. Dial up the count, or remove the species.
- All fish are bottom-dwellersTop and middle of the tank will look empty, and surface food drops uneaten. Add a mid or top species (rasboras, danios, hatchetfish) to use the whole water column.
Full attributes
Every parameter, side by side| Parameter |  FishOtocinclus (Common)Otocinclus vittatus |  FishReticulated Hillstream LoachSewellia lineolata |
|---|---|---|
| Category | Fish | Fish |
| Origin | Northern and central South America | Central and southern Vietnam |
| Family | Loricariidae | Gastromyzontidae |
| Temperature | 20–26 °C | 20–24 °C |
| pH | 6.0–7.5 | 6.5–7.5 |
| Hardness (dGH) | 2–10 | 4–15 |
| Flow rate | Medium to High | Very High |
| Min tank | 60 L | 75 L |
| Adult size | 3.5–5 cm | 5–7 cm |
| Difficulty | 3 / 5 | 3 / 5 |
| Lifespan | 3–5 yrs | 8–10 yrs |
| Diet | Herbivore (algae) | Herbivore (biofilm and algae) |
| Water column | Bottom (grazes everywhere) | Bottom (sticks to surfaces) |
| Schooling | Yes | Loose group |
| Plant safe | Yes | Yes |
| Shrimp safe | Yes | Yes |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Otocinclus (Common) and Reticulated Hillstream Loach together?
Yes. Their temperature and pH ranges overlap around 20 to 24 °C and pH 6.5 to 7.5, so one set of water conditions keeps both comfortable. Match group sizes and cover the usual planted-tank basics and they share a tank fine.
Which is easier to keep, the Otocinclus (Common) or the Reticulated Hillstream Loach?
They sit at the same care level, both middle-of-the-road, so neither is the obvious beginner pick. The decision is really about the look you're after.
Do Otocinclus (Common) and Reticulated Hillstream Loach need the same water?
Close to it. Aim for 20 to 24 °C and pH 6.5 to 7.5 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Otocinclus (Common) and the Reticulated Hillstream Loach?
Space. The Otocinclus (Common) wants about 60 litres minimum and the Reticulated Hillstream Loach around 75, so tank size can settle it.