Theme Conflict

On my dashboard, I keep being shown that I need to update my theme “Catch Responsive”, but am using Pluto as my theme. I understand that Pluto is a child theme.

Does that mean that “Catch Responsive” is the anchor theme for my site and Pluto is an additional theme overlaying the first one? If not, can I get rid of “Catch Responsive” so I don’t have to keep seeing the update notices?

If so, how do I do that? I don’t see anywhere on the Dashboard to delete themes. I am guessing I need to go into the editor, but don’t know where I would go. Thanks much for the assistance.