The live LMB may for a while but the ability of the LMB to reproduce can be greatly reduced as the GShad wipe out the plankton the yoy LMB need to survive. Also as a pond gets crowded LMB sometimes stop reproduction efforts entirely. So you end up with very large GShad that nothing can eat and reproduction/recruitment of everything else is suppressed. In that case your pond may contain all the fish it can support and 70% may be GShad.