Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Botanical name of figs is Ficus.
Weeping Fig = Ficus benjamina
Edible Fig = Ficus carica
There are many more, mostly tropical trees and shrubs, and at least one vine. Many are house plants.
Yes, the latex sap would worry me, too. If Tom says it is broken down after a year or two, the perhaps test some with just a few fish.
If you have some fig wood, then put it out in the garden where it will be alternately wet and dry for a year or so, this will help age it, and break down any toxins.