1. Deployment: Hystrix is a library specifically designed to handle network communication between distributed services within a single application, while Zookeeper is a separate distributed coordination service used for managing configurations, naming services, and synchronizing distributed services across multiple applications or nodes.
2. Purpose: Hystrix focuses on providing fallback mechanisms and circuit-breaking functionalities to ensure the resilience of individual services, while Zookeeper specializes in maintaining consistent and centralized information across distributed applications through its hierarchical key-value store.
3. Scalability: Hystrix primarily deals with managing communication failures and latency between services within the same application, whereas Zookeeper is designed to handle large-scale distributed systems by providing a reliable and scalable infrastructure for coordination and synchronization.
4. Consistency: Hystrix focuses on ensuring the availability and stability of individual services by isolating and handling failures locally, while Zookeeper maintains consistency and coherence in distributed systems by enforcing distributed consensus and coordination protocols.
5. Monitoring: Hystrix offers built-in monitoring and metrics capabilities to track the health and performance of individual services, while Zookeeper provides monitoring and administration tools for managing the state and health of the distributed system as a whole.
6. Flexibility: Hystrix is more tailored for microservices architectures within a single application, offering fine-grained control over individual service interactions, whereas Zookeeper is a versatile tool that can be used to support a wide range of distributed applications and systems beyond microservices.

In Summary, Hystrix is focused on resilient communication within a single application, while Zookeeper is geared towards managing coordination and consistency in distributed systems.