There is a 0.3% fee for each trade. This fee is shared by all liquidity providers pro-rata to their shares of the liquidity pool.
There is no protocol fee.
Acala stablecoin Surplus
AcalaSwap is used by the Acala stablecoin protocol for collateral liquidation. A portion of the stability fee surplus in the form of stablecoin can be configured to distribute to liquidity providers of the respective stablecoin pools.