Hi Nguon,
Firstly welcome to the forums
you will get plenty of good advice here, as I experienced being a new member too.
I also have a pair of clowns which was the first fish I added to the aquarium once it cycled.
I’m no expert - in fact far from it but the majority of questions I’ve raised, the first response was the following:
How long has the aquarium been set up for
Salt level
Nitrate and PH levels
What else is in the aquarium
For your particular question and concern, what is it you are trying to feed them and does it differ to what the Fish shop feeding then.
For the first couple of days, my two clowns are very little but then became very happy in their new homes and now they don’t stop eating haha. I always vary their food from a mixture of brine shrimp Mysis seaweed to flakes and tiny pellets. From advise I’ve been given on here, it’s a good move to vary a diet.
Anyways, let us know a bit more about your aquarium and I’m sure the more expert members can assist you further
Little smudge