In most cases, yes. Adding a new pet to your plan mid-year typically qualifies as a Qualifying Life Event, which means you don't have to wait for your next open enrollment period to make the change.
To get started, contact your HR team or the benefits platform you enrolled through. They can confirm whether adding a pet is permitted under your specific plan and walk you through the process.
If you purchased your Wagmo plan directly rather than through an employer benefit, you can add a pet anytime from your Wagmo dashboard. Just log in and click "Add Pet."