Can hillstream loaches live with arowanas?

Verdict

No. Hillstream loaches and arowanas should not share a tank. An adult silver arowana eats fish that fit in its mouth, and at 2.5 inches hillstream loaches do.

Hillstream loach68–75°F · pH 6.5–7.5

Silver arowana75–86°F · pH 6–7

What to watch

Deal breakerAn adult silver arowana eats fish that fit in its mouth, and at 2.5 inches hillstream loaches do.
Deal breakerArowanas are aggressive and will bully peaceful hillstream loaches.
Watch outThey only share 75°F. Keep the heater set there and steady.
Watch outArowanas grow to 36 inches and need 250 gallons, far more than a tank set up for hillstream loaches.

What works

pH 6.5–7 suits both.
They use different parts of the tank: hillstream loaches the bottom, arowanas the top.

Water side by side

The green band is the temperature range both can live in.

The green band is the pH both tolerate.

Size to scale

Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

	Hillstream loach	Silver arowana
Temperature	68–75 °F	75–86 °F
pH	6.5–7.5	6–7
Adult size	2.5 in	36.0 in
Minimum tank	20 gal	250 gal
Temperament	Peaceful	Aggressive
Swims at	Bottom	Top
Group	Groups of 3+	One per tank
Diet	Herbivore	Carnivore

Better tank mates for hillstream loaches

All hillstream loach tank mates

Questions

Can hillstream loaches live with arowanas?

No. Hillstream loaches and arowanas should not share a tank. An adult silver arowana eats fish that fit in its mouth, and at 2.5 inches hillstream loaches do.

What temperature suits both hillstream loaches and arowanas?

75–75 °F. Hillstream loaches need 68–75 °F, arowanas need 75–86 °F.

What size tank do hillstream loaches and arowanas need together?

At least 250 gal, set by the silver arowana. Add space for each extra fish.