The Lynx VE.Can has a space for a main fuse. This space has been designed to fit a CNN fuse. A 325A/80V fuse is available from Victron Energy (CIP140325000-Fuse CNN 325A/80V for Lynx shunt" or use another CNN fuse by Littlefuse. Although the distance between the fuse mounting bolts is designed for a CNN fuse but it might also be possible to fit other fuse types in this space. The fuse mounting bolts are M8 and their centres are 63mm apart.
Always use fuses with the correct voltage and current rating. Match the fuse rating to the maximum voltages and currents that potentially can occur in the fused circuit. For more information on fuse ratings and fuse current calculations see the Wiring Unlimited book.