Hillstream loach care guide
Also called: Reticulated hillstream loach, Tiger hillstream loach, Gold ring butterfly sucker, Vietnamese hillstream loach
The hillstream loach is a flat, tiger-patterned loach from Vietnam that clings to rocks and grazes algae. It needs cool, fast-moving, oxygen-rich water at 20–24°C (68–75°F), smooth rocks coated in biofilm, and a lid with no gaps.
Hillstream loaches need a tank of at least 20 gallons (76 L), a group of 3 or more, and water at 20–24°C (68–75°F) with a pH of 6.5–7.5. They grow to about 6.5 cm (2.6 in) and are peaceful.
Plan a tank with hillstream loachesSee all tank mates
Hillstream loach quick facts
| Scientific name | Sewellia lineolata |
|---|---|
| Family | Gastromyzontidae |
| Origin | Fast hill streams of central Vietnam, possibly also southern Laos |
| Adult size | 6.5 cm (2.6 in) |
| Minimum tank | 20 gallons (76 L), at least 75 cm (30 in) long |
| Temperature | 20–24°C (68–75°F) |
| pH | 6.5–7.5 |
| Hardness (GH) | 4–12 dGH |
| Group size | 3 or more (group) |
| Temperament | Peaceful |
| Swims at | Bottom |
| Diet | Omnivore |
| Care level | Moderate |
| Lifespan | 6–10 years |
| Safe with shrimp? | Yes, shrimp-safe |
| Safe with plants? | Yes |
- Cold-water species: no heater needed in most homes.
- Known jumper: keep a tight-fitting lid.
Tank setup
Three or more need at least a 20-gallon long (76 L) tank about 30 in (75 cm) long; a wide footprint gives more grazing room. Copy a stream with smooth rounded rocks, pebbles, wood and hardy plants like Anubias and Java fern. Use a strong filter or an extra powerhead for flow, with a sponge over the intake. Cover every gap, because they climb glass and escape.
How many hillstream loaches in a tank?
The smallest common tank that suits hillstream loaches is a 20 gallon long. 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 | Hillstream loaches (alone) |
|---|---|
| 3 gallon | Too small |
| 5 gallon | Too small |
| 10 gallon | Too small |
| 15 gallon | Too small |
| 20 gallon | Too small |
| 20 gallon long | 3–13 |
| 29 gallon | 3–19 |
| 40 gallon | 3–26 |
| 55 gallon | 3–36 |
| 75 gallon | 3–49 |
| 125 gallon | 3–82 |
What you need for hillstream loaches
Sized for a 20 gallon long tank, the smallest common size that suits a group of 3 hillstream loaches. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.
Tank and equipment
- 20 gallon long 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 20 gallons (opens Amazon in a new tab)The water alone weighs about 167 lb (76 kg), before glass, gravel and rock. How to choose
- Hang-on-back filter rated 80–120 GPH (opens Amazon in a new tab)Community tank: 4–6 times the tank volume per hour. How to choose
- About 45 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 30 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 hillstream loaches
- Sinking pellets or wafers (opens Amazon in a new tab)Bottom feeders need food that reaches the floor.
- Caves and hides (opens Amazon in a new tab)Gives shy and territorial fish their own space.
- Tight-fitting lid for a 20 gallon tank (opens Amazon in a new tab)Hillstream loach can jump out of an open tank.
Product links go to Amazon search results. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Disclosure.
Water parameters
Keep it cool at 20–24°C (68–75°F), with pH 6.5–7.5 and soft to moderately hard water. High oxygen matters most, so aim for strong surface movement and a filter that turns the water over many times per hour. In most homes it needs no heater. Long spells above about 25°C (77°F) stress it, especially when oxygen is low.
Best tank mates for hillstream loaches
These popular species share hillstream loaches' water needs and temperament. See the full list of 33 good matches.
Cherry shrimp
3 cm (1.2 in) · 20–27°C (68–81°F)
Neon tetra
3.5 cm (1.4 in) · 21–25°C (70–77°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)
Fancy goldfish
15 cm (5.9 in) · 18–23°C (64–73°F)
Zebra danio
5 cm (2 in) · 18–25°C (64–77°F)
Ramshorn snail
2 cm (0.8 in) · 21–27°C (70–81°F)
Amano shrimp
4.5 cm (1.8 in) · 20–27°C (68–81°F)
Avoid keeping hillstream loaches with
- Oscar: Oscar can eat hillstream loaches: they're small enough to fit in its mouth once it's grown.
- Boesemani rainbowfish: They need different temperatures: Hillstream loach 20–24°C (68–75°F), boesemani rainbowfish 26–29°C (79–84°F).
- Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful hillstream loaches.
- Clown loach: They need different temperatures: Hillstream loach 20–24°C (68–75°F), clown loach 25–30°C (77–86°F).
- Convict cichlid: Convict cichlid is aggressive and will bully or injure peaceful hillstream loaches.
- Discus: They need different temperatures: Hillstream loach 20–24°C (68–75°F), discus 28–30°C (82–86°F).
Feeding
It grazes algae, biofilm and tiny animals off rocks and glass all day. A tank rarely grows enough algae to feed it, so add algae wafers, gel foods and blanched vegetables. Offer frozen brine shrimp or bloodworms once or twice a week.
Behavior
Peaceful with other fish, but its own kind, mostly males, spar over the best grazing spots. These scuffles rarely cause harm, and rocks that block lines of sight help. Keep three or more, and five or six if there is room. A single fish or a pair takes the brunt of the bullying. Good tankmates are cool-water fish like white cloud minnows and danios, plus shrimp and snails.
Breeding
It is one of the easier loaches to breed in a mature tank with rounded gravel, lots of algae and good flow. A few warmer days at 25–26°C (77–79°F) followed by a cool water change can trigger spawning. Males are slimmer with a squarer head, and their front fins jut out sideways more than the female's. Fry eat infusoria, then baby brine shrimp or microworms.
Tips from experienced keepers
- Only add it to a mature tank with algae and biofilm already on the rocks.
- Put a sponge on the filter intake and close every gap in the lid.
- Keep three or more, never one or two. A group spreads out the sparring.
- Watch summer heat. A fan or a cooler room keeps it under 24°C (75°F).
- Don't house it with Borneo suckers or other flat loaches that compete for the same rocks.
Frequently asked questions
Can hillstream loaches live in a tropical tank?
They prefer cooler water at 20–24°C (68–75°F). They can cope with the cool end of a tropical tank if flow and oxygen are strong, but long-term warmth above about 25°C (77°F) stresses them.
Do hillstream loaches eat algae?
Yes, they graze soft algae and biofilm all day. They still need extra food such as algae wafers and gel food, because most tanks don't grow enough algae to feed them.
Are hillstream loaches safe with shrimp?
Yes. They graze biofilm and leave dwarf shrimp alone, which makes them a good fit for a cool, well-oxygenated shrimp tank.
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.