You would usually find that the shovelnose would grow quicker than the ghost knife, however if well fed the BGKs can grow surprisingly quickly.
I have my BGK in with 2 lima shovelnose, a spotted shovelnose and various other large pims. It is about 9" or so now, and i can see it still growing well. When i bought it less than a year ago it was about 4.5-5" so it has nearly doubled in size in less than a year.
You don't provide any tank size info, but if you didnt already know, Lima Shovelnose can grow to 18" in tanks, and BGKs usually grow to at least 14" but in a good sized tank 16" would easily be expected. Both also need the big tank, but for different reasons. The Limas if spooked will skittishly dart to the other side of the tank, often resulting in a bash on the nose because there isnt enough space for them to run and hide. BGKs on the other hand can actually be quite active and their forward and back gliding propels it from one side of the tank to the other rather quickly, and so when it is quite big it needs plenty of space to roam.
Ben
