Welcome!!! Would love to see some pics of your clowns and tank.
if you only have 2 clowns, I wouldn't feed anymore than 1/2 of a cube of frozen per day, spread in 3 feedings or so ideally. Easy rule of thumb is if they don't finish all the food in 5 minutes, you gave them too much and risk waste/water fouling.
Realistically though, clownfish are omnivores and need a more varied diet. You should have a quality pellet or flake food as a staple. What I use with success is below. Having them accustomed to dry food also makes it simple to set an auto-feeder if you ever have to leave the tank alone for a while due to travel etc.
ON Formula 1 flakes:
https://amzn.to/3zw8ZE7
ON formula 2 flakes:
https://amzn.to/3ZMjihP
Hikari Marine Pellets:
https://amzn.to/4eo1IoN