Yikes!
This is turning into a nightmare. But, on the flip side...
@Deeda is right in that even large fish will have really good shipping outcomes if set up and packed out right. The way you prepped out those Uaru's and then packed them up for shipping, sounds very good to me. The delay of a day or so, should not cause a disaster.
I've been out of the fish shipping game for a while now. But, I am still actively breeding and shipping baby (and sometimes adult sized)
Boa constrictor longicauda, (smaller, rare locality, Boa Constrictors). Unfortunately, I have to use the shipping license of these guys when doing that through FedEx.
Reptile shipping- Ship live reptiles including snakes and lizards securely and affordably with Ship Your Reptiles
shipyourreptiles.com
And yes... I still purchase and charge for the insurance ($$$). But, after almost 10 years of using that outfit, I've never had a single shipping problem.