Stake Pools that produce blocks earn a share of the Epoch rewards. 

These rewards are made up of:

• the Cardano network fees paid by the transactions that occurred in the Epoch; and
• A small portion of the Cardano ADA reserves (currently 0.3%) 

which are added together to create the total “pot” of rewards that are to be distributed.

A portion of that total rewards “pot” (currently 20%) is added to the Cardano ADA Treasury, which funds future Cardano development and the overall evolution of the network.  

The remaining rewards (80%) are distributed to the Stake Pools who produced blocks in the Epoch, given that they have fulfilled their role properly.  

For each Stake Pool, the Pool’s fixed fee and staking margin are deducted from the total rewards earned.

Finally, the individuals who staked their ADA with that Stake Pool will receive ADA rewards, in proportion to their share of the total stake for that Pool.