Amelle, read the article on Tables. Did you turn on display of gridlines for tables?

Cell markers are like paragraph marks. They do not, themselves, use any space in a document. Rather, they indicate a collection of formatting information for the cell (paragraph) that precedes them.

You do not want to be deleting the cell marker. That is one of the easiest ways to turn a table into a mess. You may want to be changing the columns themselves. You may be wanting to merge or split cells.

By default, each cell has an indent on the right and on the left. There is also "padding" on cells.

I have never found the vertical ruler a good way to modify anything in a document. I display it for information.

You may also want to see if there is spacing before formatting in the following paragraph, the one you want to be closer. That is the paragraph that starts "Tap/Ballet." This would be in the paragraph formatting.