The Wild Thornberrys (1998)

S2E8 Koality and Kuantity

The Thornberrys realize that koalas have vanished from their natural habitats. Determined to get to the bottom of the situation, Eliza sets out to investigate and uncovers that Kip and Biederman are behind the sinister scheme. Now, it's up to Eliza to put a stop to their plan before they eliminate an entire species!