Ghost/Spectre Dragon not taming

[R0b0r0b]

Logs: N/A

Steps to Reproduce:

1. Find Ghost Dragon egg (or convert another egg into it)
2. Wait for it to hatch
3. Try and fail to feed it fish to tame it

Description of issue: So, I'm playing on a small multiplayer modpack, and I found a Spectre dragon egg in a temple chest. It hatched normally, but wouldn't let me tame it (even though I was using raw salmon). I saw somewhere that you need to wait for the dragon to grow up now before you can tame it, but that didn't work either. The dragon also won't sit or equip a saddle - which I assume is because it's not tamed.