How to tell the fish i am feeding is a Molly

Hi, i am new here. I hv to feed mollies to my lionfish and undulate trigger and I am little confused what is the difference between mollies and rosies. I think my lfs is fooling me by giving wrong fishes in place of mollies. Everytime he give me different colour fishes which forces me to think that he is giving me wrong fishes

 

There are many different types of mollies. Can you send a picture of the fish?

 

There are many different types of mollies. Can you send a picture of the fish?

Next time when I feed then, I will surely post here

 

Next time when I feed then, I will surely post here

That'll help. If nothing else, you could google a Molly and see if they look alike

 

There are many different types of mollies. Can you send a picture of the fish?

I found a pic. This was a black one. Sometimes he give orange coloured and yellow coloured

 

I found a pic. This was a black one. Sometimes he give orange coloured and yellow colouredView attachment 888109

That does appear to be a molly. Likely the others are too

 

Thats 100% a molly