You will be fine, as said before it would be easier to add the radiata first, or make sure it is eating aggressively in QT before adding the volitan. Volitans try to eat all the food that goes into the tank, sometimes making it harder for smaller fish with the same diet to get enough food. My 2 large volitans even try to eat the mysis I put in for my other fish even though it is way to small for them.