I think the Peru piraiba bit up the vultures overnight. Should have moved the vultures to the 1800 gal instead of the 4500 gal or at least should have left pipes and nets, as I usually do, in the 4500 gal overnight or for a few days to give the newcomers an easier time to adjust to the new tank without or with less harassment because installing new things in a tank causes caution and light stress for the old inhabitants.
Moved the 2 vultures to the 1800 gal.