No.
Hydra is a layer-two solution which works "on top of" Cardano. A hydra-node which implements the Hydra Head protocol will run alongside the cardano-node and provide an isomorphic state channel which has the same transaction format and ledger rules as Cardano, but with a much simpler consensus. The fact that not the whole network needs to agree to reach consensus in a single Hydra Head, but only the participants of a particular Head, makes this faster & cheaper than to process transactions on the mainchain.