Can rainbow sharks live with flowerhorns?

Verdict
No

No. Rainbow sharks and flowerhorns should not share a tank. Flowerhorns are aggressive and much bigger than rainbow sharks.

Rainbow sharkRainbow shark72–80°F · pH 6.5–7.5 FlowerhornFlowerhorn80–89°F · pH 7–8

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 80°Rainbow shark 72–80°Flowerhorn 80–89°
The green band is the temperature range both can live in.
456789Both: 7–7.5Rainbow shark 6.5–7.5Flowerhorn 7–8
The green band is the pH both tolerate.

Size to scale

Rainbow shark · 6 inFlowerhorn · 12 in0"2"4"6"8"10"12"
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

Rainbow sharkFlowerhorn
Temperature72–80 °F80–89 °F
pH6.5–7.57–8
Adult size6.0 in12.0 in
Minimum tank55 gal75 gal
TemperamentSemi-aggressiveAggressive
Swims atBottomMiddle
GroupOne per tankOne per tank
DietOmnivoreCarnivore

Better tank mates for rainbow sharks

All rainbow shark tank mates

Questions

Can rainbow sharks live with flowerhorns?

No. Rainbow sharks and flowerhorns should not share a tank. Flowerhorns are aggressive and much bigger than rainbow sharks.

What temperature suits both rainbow sharks and flowerhorns?

80–80 °F. Rainbow sharks need 72–80 °F, flowerhorns need 80–89 °F.

What size tank do rainbow sharks and flowerhorns need together?

At least 75 gal, set by the flowerhorn. Add space for each extra fish.