Pachira are very tough trees and require little attention. The biggest killer is overwatering.
It's happiest in bright indirect light, but can cope in lower light conditions. Direct sunlight can scorch the leaves.
The pachira grows on the riverbank, hence 'Aquatica', but doesn't need as much watering as you'd expect. Storing water in its bulbous trunk. Water when the soil has dried out. Water less in winter.
Yellowing or wilted leaves: too much water.
Brown or crispy leaves: too little water.