I think you can refer to Minecraft link for details about how to use mudfish for Minecraft. :-) If you have any questions, please let me know.

Awesome thank you, wasn't sure if it was possible to create custom items :D

I'd checked you tried to create your own item. However please be aware that when the custom item is created, a mudfish for that item is automatically picked unless you specify the mudfish node you'd like to use. To optimize the ping, you should explicitly set the mudfish node using item configuration menu. Please let me know if you're encountering any issues. :-)