A multi-well fluid container that includes a container body is provided for use in an in vitro diagnostics automation system. The container body includes a first well having a first well size configured to hold a first fluid and an openable first well closure that covers a first well opening. The first well opening provides access to the first fluid in the first well when the openable first well closure is opened. The container body also includes a second well having a second well size configured to hold a second fluid and having an openable second well closure that covers a second well opening. The second well opening provides access to the second fluid in the second well when the openable second well closure is opened. The first well size of the first well is different than the second well size of the second well.