Two knee-jerks.
There is no one answer to the weaning, as the link I posted describes. Seems to be two groups of reports - easy for ones and hard for the others. The commonality that was found was - start right away and start when they are young and be persistent.
Trout being a cold-water fish is high in fat. As an occasional snack it could be fine for a tropical predator like the juruense but I'd not use it as a staple. It is designed to feed on lean tropical cuisine AFAI understand. It may develop digestive or other probems sooner or later. This is also one of the reasons food like gold-fish are bad for tropical predators.
On the other hand, e.g., Arapaimag feeds his 52,000 gal tank with mackerel regularly, another fatty fish. But this is only a part of the varying diet he offers his fish.