I think T.corticale is one of biggest species and can reach 8-9cm (3-3,5 inches). Asperum are smaller, they reach approx.3cm (1 inch) and can be feed by anythingFrom fruitflies to big insects. Here are adult frogs:
You can also saw articles of Eugeny Ryboltowsky (is it translation correct?) here: Articles - breeding of rare Vietnamese amphibians