Fish comparison
Otocinclus (Common) vs Siamese Algae Eater
How the Otocinclus (Common) and Siamese Algae Eater compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Otocinclus (Common) vs Siamese Algae Eater
The Otocinclus (Common) and the Siamese Algae Eater 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 24 to 26 °C and pH 6.5 to 7.5, so a single tank can suit either one. The Siamese Algae Eater is the more forgiving of the two, which matters if this is an early tank, while the Otocinclus (Common) rewards a bit more attention. If tank space is tight, the Otocinclus (Common) needs less room to feel settled; give the Siamese Algae Eater 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
- Siamese Algae Eater24–28 °C
pH
- Otocinclus (Common)6–7.5
- Siamese Algae Eater6.5–7.5
Hardness
- Otocinclus (Common)2–10 dGH
- Siamese Algae Eater5–15 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 |  FishSiamese Algae EaterCrossocheilus langei |
|---|---|---|
| Category | Fish | Fish |
| Origin | Northern and central South America | Mainland Southeast Asia (Thailand, Malaysia, Indonesia) |
| Family | Loricariidae | Cyprinidae |
| Temperature | 20–26 °C | 24–28 °C |
| pH | 6.0–7.5 | 6.5–7.5 |
| Hardness (dGH) | 2–10 | 5–15 |
| Flow rate | Medium to High | Medium to High |
| Min tank | 60 L | 150 L |
| Adult size | 3.5–5 cm | 12–15 cm |
| Difficulty | 3 / 5 | 2 / 5 |
| Lifespan | 3–5 yrs | 8–10 yrs |
| Diet | Herbivore (algae) | Omnivore (heavy algae grazer) |
| Water column | Bottom (grazes everywhere) | Bottom (grazes everywhere) |
| Schooling | Yes | Loose group |
| Plant safe | Yes | Yes |
| Shrimp safe | Yes | Yes (adults safe with adult shrimp) |
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 Siamese Algae Eater together?
Yes. Their temperature and pH ranges overlap around 24 to 26 °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 Siamese Algae Eater?
The Siamese Algae Eater is the easier of the two, closer to beginner-friendly, while the Otocinclus (Common) leans middle-of-the-road.
Do Otocinclus (Common) and Siamese Algae Eater need the same water?
Close to it. Aim for 24 to 26 °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 Siamese Algae Eater?
Temperament is the big one. The Otocinclus (Common) is peaceful and the Siamese Algae Eater is territorial when breeding, which changes who you can house them with.