How to fix a half transparent texture?

Hi, i'm idrus and i'm a student. i have a texture problem on my final project. i was making augmented reality, i'm using "unity 2018. 1. 1f1 personal" and "Cinema 4D R18". I have exported ".fbx" file from cinema 4D. i textured 7 objects of animal and i didn't use uv map to texture them. i used basic way, i just selected every polygon then i put the color because the concept in low poly, it was look good in cinema 4D but. after i put it in unity, the texture changes. i don't know how to fix this, i hope you guys can help me. im sorry if my english is not really good.

Thanks anyway :)

A Half Transparent Texture

Texture that i want