first off you posted this in marketplace should go in the catfish section
secondly "merodontus tigrinus" is the scientific name, "tigrinus shovelnose" is a common name, most people just say "tig" or "tigrinus", both refer to the same thing. if you see them for $40 this is probably not a tigrinus, but another similar catfish such as TIGER (not TIGRINUS) shovelnose, or TSN. Tigrinus catfish cost around $130+++ for juveniles and $400+++ for adults. TSN cost around $5-$50++