How do i get a compatible Java 3d model without having to pay for it?

Hi

I just wanted to make a zebra on my mod, however it doesn't have a horse model on MCreator, so i found a site that sells java 3d models, and i downlaoded a existing horse model, and when i was importing to MCreator, it appeared a message saying that the model is unconpatible, and i didn't used the model because it will probaly break minecraft, the only thing that remains, it's your help to get a compatible horse model that it's free.