The COPAS™ FP 1000 (Complex Object Parametric Analyzer and Sorter – Union Biometrica) is a flow cytometer for large objects featuring a fluidic path and flow cell optimized for zebrafish larvae. The instrument is equipped with an X-Y stage to permit the dispensing of larvae into multi-well plates. Using the FlowPilot™ software several parameters like size and fluorescence, even in different parts of the larvae can be measured and selected as criteria for sorting. A 488 nm solid state laser is used to measure both the size and optical density of the objects. For fluorescence excitation our COPAS™ FP system is equipped with a 488nm, 561nm and a 405nm laser. We typically use the COPAS™ system to sort zebrafish according to fluorescence into 96 well plates.