I think you must be referring to a (hearsay?) phenomenon that exists in Asian fish forums about the tig catfish, that is that they die from stress of just being moved between tanks, of being netted and taken out of water.
Asian Exotics
I heard it from our peer Cy, whom I am tagging, the one and only time I came across this. I didn't believe this. Then, over 1.5 years I lost 6 adult tigs. I still do not think this was due to the move at all. I had other completely unrelated fish die in that tank with the same exact symptoms. However, this doesn't rule out the stress that could have weakened tigs' immune system and thus they were overcome by the same infection as those other tank mates and died over 1.5 year period, 6 out of 8. Two are still ok. Anyhow, this sounds like a long stretch, but cannot be ruled out completely.
So, as for the tigs, IDK, I don't believe this, it doesn't sound plausible but I cannot prove it.
If you are extending this fear onto the genus-kin of tig, that is the piraiba, that'd be a first for me to hear this.
IME I haven't had any problems moving piraiba from tank to tank even at 3 feet, as yours is, you can see our videos on how we do it on our channel (type pillowcase and blanket case in the search). But never long distance, just from tank to tank in our facility.
Clove oil always helps, for sure. The fear is overdosing and euthanizing the fish. Err on the safe side I'd say. And use the largest transport container you can afford, if you value the fish a lot. Like even rent a truck / van that can carry 250 gallons of water in say a 500 gal tub.
