I would be wary of goldfish feeders that size. Small TSN have very soft mouths but big appetite ideas and it might damage its mouth on a larger goldfish. I might be being anal but baby TSN are $300-$400 each here in Australia so I wouldnt be using those size goldfish till the catfish is about twice its current size with a stronger bill.
I'd ship you some but I think the shipping cost alone would kill you LOL

