Ivan wrote:

It's attracting ants.. Lots of tiny red ants ..
I picked some up with my hands and killed them, but the closer I
looked the more ants I saw..

How do I get rid of these without harming the seedling?

You need to determine if they are nesting in the soil or just attracted
to some other issue such as honey dew from aphids that may be on the plant.

Lar