I want create a fabric mod with custom creatures for 1.20.1

Hi everyone, I write here searching help please!! 

I want to create a mod with custom creatures for my map. But my problem is that i play on fabric versions, i have all my others mods on it. I want to know if there is an option to create that on fabric version 1.20.1. 

if its imposible, i try to change to forge, but if ther is another option, i want to heard it to valorate.

Thanks.