GatsbyContentfulFluid, is there a presentationWidth property?

Sorry can’t find this in any docs. I have a Gatsby template where I want the fluid image to not exceed the original image’s width. This seems to be available in GatsbyImageSharp, here are the docs:

but for the life of me can’t figure out how to use this with contentful. My Graphql query looks like:

export const query = graphql`
  query($slug: String!) {
    contentfulWork(slug: { eq: $slug }) {
      heroImage {
        fluid(maxWidth: 1800) {
        file {

any help greatly appreciated, thanks.