I was in the middle of making a fireball and I encountered this, I do not know if its a bug or something I set up incorrectly or a mesh problem.
Can someone be help to solve the problem? Thank you for your time 
(Edit: I forgot to mention that this is a Blue Print where I placed 2 meshes on over the other and are animated with a shader. Both materials are Translucent and default lit. I also tried to use additive and Unlit but the problem stays.)
Put that into particle system and set sort order 0 to the cone and 1 for the trail. It should fix the problem
if that still doesnt fix it, duplicate the outer ‘‘shell’’ and make those both shells only one sided. One oriented Out, the other one in. That combined with correct sorting of the trail should make it work correctly.
Thank you for the suggestion and it solved the problem! I appreciate it.
The other day I was looking at some premade effect in the marketplace and could not understand why they had to same meshes but one of the two had the shell inwards and I am guessing this is why!
Thank you for sharing your knowledge I will deffo use this method too.
I am glad that I was able to help 