Siamese algae eater care guide
Also called: SAE, Siamese algae-eater, True Siamese algae eater, Crossocheilus siamensis, Crossocheilus langei
The Siamese algae eater is a fast, slim algae grazer famous for eating black beard algae. It's sold small but reaches about 6 in (15 cm), so it needs at least a 55-gallon (208 L), 4 ft (120 cm) tank with clean, well-oxygenated water.
Siamese algae eaters need a tank of at least 55 gallons (208 L), and water at 22–26°C (72–79°F) with a pH of 6.5–7.5. They grow to about 15 cm (5.9 in) and are peaceful.
Plan a tank with siamese algae eatersSee all tank mates
Siamese algae eater quick facts
| Scientific name | Crossocheilus oblongus |
|---|---|
| Family | Cyprinidae |
| Origin | Streams and rivers of mainland Southeast Asia and the Malay Peninsula (aquarium fish are farm-bred) |
| Adult size | 15 cm (5.9 in) |
| Minimum tank | 55 gallons (208 L), at least 120 cm (47 in) long |
| Temperature | 22–26°C (72–79°F) |
| pH | 6.5–7.5 |
| Hardness (GH) | 5–15 dGH |
| Group size | Can live alone |
| Temperament | Peaceful |
| Swims at | Bottom |
| Diet | Omnivore |
| Care level | Moderate |
| Lifespan | 5–10 years |
| Safe with shrimp? | No, eats shrimp |
| Safe with plants? | Mostly (nibbles soft plants) |
- Known jumper: keep a tight-fitting lid.
Tank setup
One fish needs at least a 55-gallon (208 L) tank that is 4 ft (120 cm) long. A group of six or more needs far more room: at least 80 gallons (303 L) and 5 ft (150 cm) long. Add rocks, driftwood and sturdy plants to rest on and to break up sight lines. Fit a tight lid, because it can jump.
How many siamese algae eaters in a tank?
The smallest common tank that suits siamese algae eaters is a 55 gallon. Here is roughly how many fit in each size when they are the only fish, based on adult size and waste output. Leave room if you want tank mates.
| Tank | Siamese algae eaters (alone) |
|---|---|
| 3 gallon | Too small |
| 5 gallon | Too small |
| 10 gallon | Too small |
| 15 gallon | Too small |
| 20 gallon | Too small |
| 20 gallon long | Too small |
| 29 gallon | Too small |
| 40 gallon | Too small |
| 55 gallon | Up to 10 |
| 75 gallon | Up to 14 |
| 125 gallon | Up to 23 |
What you need for siamese algae eaters
Sized for a 55 gallon tank, the smallest common size that suits siamese algae eaters. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.
Tank and equipment
- 55 gallon aquarium (tank or kit) (opens Amazon in a new tab)Bigger tanks are more stable and easier for beginners. How to choose
- Aquarium stand for 55 gallons (opens Amazon in a new tab)The water alone weighs about 459 lb (208 kg), before glass, gravel and rock. How to choose
- 2 adjustable heaters, 75 W each (opens Amazon in a new tab)Holds about 75 °F (24 °C) in a room at 65 °F (18 °C). Two heaters keep the tank warm if one fails. How to choose
- Aquarium thermometer (opens Amazon in a new tab)Check it daily: heaters can fail stuck on or off. How to choose
- Hang-on-back filter rated 220–330 GPH (opens Amazon in a new tab)Community tank: 4–6 times the tank volume per hour. How to choose
- About 75 lb of aquarium gravel (opens Amazon in a new tab)Enough for a layer about 2 in (5 cm) deep. Smooth gravel suits most community fish. How to choose
- Water conditioner (dechlorinator) (opens Amazon in a new tab)Removes chlorine and chloramine from tap water. Seachem Prime is a popular, concentrated choice. How to choose
- Liquid test kit (ammonia, nitrite, nitrate, pH) (opens Amazon in a new tab)Liquid kits are more accurate than strips. The API Freshwater Master Test Kit is the common choice. How to choose
- Gravel vacuum (siphon) (opens Amazon in a new tab)Cleans the gravel and does the water change in one go. How to choose
- LED aquarium light, about 48 in long (opens Amazon in a new tab)Match the light to the tank length. Basic LEDs grow easy plants. How to choose
Food and extras for siamese algae eaters
- Sinking pellets or wafers (opens Amazon in a new tab)Bottom feeders need food that reaches the floor.
- Tight-fitting lid for a 55 gallon tank (opens Amazon in a new tab)Siamese algae eater can jump out of an open tank.
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Water parameters
Keep it at 22–26°C (72–79°F), pH 6.5–7.5 and soft to moderately hard water. It comes from flowing streams, so it wants clean water, high oxygen and some current. Only add it to a fully cycled tank and do weekly partial water changes.
Best tank mates for siamese algae eaters
These popular species share siamese algae eaters' water needs and temperament. See the full list of 85 good matches.
Betta fish
6.5 cm (2.6 in) · 24–28°C (75–82°F)
Nerite snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Guppy
5 cm (2 in) · 22–27°C (72–81°F)
Dwarf gourami
7.5 cm (3 in) · 24–28°C (75–82°F)
Panda corydoras
4.5 cm (1.8 in) · 21–25°C (70–77°F)
Bronze corydoras
7 cm (2.8 in) · 21–26°C (70–79°F)
Zebra danio
5 cm (2 in) · 18–25°C (64–77°F)
Angelfish
15 cm (5.9 in) · 24–29°C (75–84°F)
Avoid keeping siamese algae eaters with
- Cherry shrimp: Siamese algae eater eats small shrimp like cherry shrimp.
- Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful siamese algae eaters.
- Convict cichlid: Convict cichlid is aggressive and will bully or injure peaceful siamese algae eaters.
- Discus: They need different temperatures: Siamese algae eater 22–26°C (72–79°F), discus 28–30°C (82–86°F).
- Electric yellow cichlid: Electric yellow cichlid is a Lake Malawi cichlid. It needs a Lake Malawi tank: hard, alkaline water (pH 7.5–8.5), plenty of rockwork and other cichlids from the same lake. Siamese algae eaters don't belong in that setup.
- German blue ram: They need different temperatures: Siamese algae eater 22–26°C (72–79°F), german blue ram 27–30°C (81–86°F).
Feeding
Young fish graze algae all day, including hair algae and the soft new growth of black beard algae. Adults prefer prepared food, so feed algae wafers or a spirulina-based food plus blanched zucchini, peas or spinach. Keep frozen and meaty foods as an occasional treat, since too much protein can make it fat. Don't overfeed if you want it to keep cleaning.
Behavior
It is peaceful toward most other species and fits well with active, similar-sized fish such as giant danios, barbs, loaches and livebearers. As adults, they form a pecking order and spar with their own kind and with look-alikes. Keep one on its own, or a group of six or more in a very large tank. In twos and threes the weakest fish is often bullied. It may chase or eat dwarf shrimp.
Breeding
It is not bred in home aquariums. Fish in the trade come from Asian farms that use hormones to spawn them. Females look a little rounder than males when mature, but young fish can't be sexed.
Tips from experienced keepers
- Buy it young if you want help with black beard algae. Adults eat less algae once they learn about fish food.
- A true SAE has clear fins and a black stripe that runs to the end of the tail. Flying foxes have a thin gold line along the stripe and black-marked fins.
- Keep one, or a group of six or more. In small groups the weakest gets bullied.
- Don't add it to a tank with red-tail or rainbow sharks, which treat it as a rival.
- Keep cherry shrimp in a separate tank. Adult SAEs often eat them.
Frequently asked questions
Do Siamese algae eaters eat black beard algae?
Yes, they are one of the few fish that eat it. They mainly eat the soft new growth, so they work best when added before an outbreak and kept a little hungry.
How big do Siamese algae eaters get?
They usually reach about 6 in (15 cm) in an aquarium. That's why they need at least a 55-gallon (208 L) tank, even though they're sold at 1–2 in.
Can Siamese algae eaters live with shrimp?
Not with dwarf shrimp like cherry shrimp, which adults often eat. Larger shrimp such as amano shrimp and snails are usually left alone.
Sources
We checked these references when writing this page. Values are for healthy long-term keeping, not survival limits. Last reviewed 2026-10-13. See our editorial policy.