Help with ID please

[TMC]

Can someone please tell me what this is the color in the picture isn't very good but in daylight it is beige with a light orange center and in blue light very bright orange center I am new to all this and just moved everything from a 50 gal to a 75 in the other tank these were smaller in diameter but looked healthy since in the new tank (only 2 days) they have more than doubled in size
1st pic daylight 2nd blue

 

[N.Sreefer]

I'm thinking blastomussa

 

[TMC]

I'm thinking blastomussa

Thanks,
If it helps any I didn't notice until after I posted but at night when the lights are out they shrink down and then swell back up when the lights come on. How fast do they multiply?