i have just seen one at my lfs hes around 10" and hes a beauty.anyone got any info on them?the guy told me they grow to 2 foot and will be fine in a 6x2x2 he is £150
If so then it sounds like a misprint of Peruno catfish which is a very rare species which this catfish is often mistaken for (or deliberately mis named as to make the fish sound more valuable).
If it is a Leiarus longibarbus then it is certainly not suitable for a 6x2x2, they are one of the fastest growing of all the big catfish and will be over 2 feet long within 2 years requiring a minimum of a 8x3x2, in anything narrower the catfish will physically attempt to leave the tank as both its barbels will be touching the sides of the tank at the same time.
They are lovely fish but unfortunately not worth anywhere near £150, you can usually pick them up in the more specialist shops for between £40 and £80 depending on their size. I have one of the slightly less common Leiarius pictus and only paid £70 for it when it was around the 10" mark 18 months ago.
Theyve had them in most times i've been down there though they dont have them on their current stocklist. Keep an eye on the online stocklist on tropical fishfinder and they should pop up sone time soon as it is now south American collecting season.