if these fish are not hard to breed, then these fish are not gonna be in the endangered status, if what you said about that old article that you had read is true then we already have bunches of them. if you think sexing these fish are easy, then you already have a pair even they are small. even asian arowana farmers are not 100% sure about the sex of their fish unless they saw it brood and lay eggs. and about breeding in a tank you said, i think only less than 5 people are successful in making their arowanas spawn and most of them are asian people in asian country