When you guys say "Tiger shovelnose" are you reffering to the false tiger (P. fasciatum) or the true tiger (M tigrinus). I assume the first of the two based on pics.
They make great hunters, and as stated grow quite fast. I've worked with some as long as 4'. I just got a pair when my arapaima came in earlier this week. They're about 4-5" and growing to exhibit size quickly!