How to dispatch an action after a rxjs event using redux-observable

Question

I'm struggling to build a store that talk to my firebase realtime database, make the insert, update was pretty straight forward using epics.

const insert = (item, ref) => {
  const newItemRef = database.ref(`${ref}/${item.id}`);
  return newItemRef.set(item);
};

export const addCardEpic = (action$) => {
  return action$.ofType(ADD_CARD)
    .filter((action) =>
      insert(action.info, 'card')
    )
    .debounceTime(400)
};

But I don't know how to make my store listen to firebase changes, currently I'm using the fromEvent operator on my componentDidMount do listen and dispatch my action right away to the store, is there a way to handle that using epics?