Abstract: The present invention includes a retrofit, in-port filter specially configured for filtering a fluid flow at a high velocity with a minimum of flow resistance. The in-port or simply port filter, is easily retrofit into a threaded pipe connection, and employs a wedge-wire coil, which serves an efficient and self-cleaning screen to prevent the intake of small particulate into the filter, without the need for moving parts, or continuous monitoring and frequent maintenance. One end of the coil is received into a coupler, the outside diameter of the coil less than the coupler's outside diameter, so that the port filter is easily retrofit into an existing fluid distribution system, with the coil insert-able into a nipple off a pipe main. The pipe can transport any fluid, but is preferably carrying water at a moderately high velocity and pressure, such as an irrigation circle-pivot tube pipe.