not really except to say yr feeding regieme is about right they can honk down the food at that size ,his belly will give it away if its slightly curved outwards then hes in good condition a sunken in belly is a sign of underfeeding or problems usually i put a 1/2 a courgette in once every two days for something that size and take the remainder (if any ) out the following night dont bother boiling it or microwaving it just put a fork in it to sink, boiling it will make it softer and it will sink easier but it will also break up faster and possibly cloud the water mine scoff 1/2 a courgette in about four hours and they aint 40cm but there is more than one alternate between courgette /cucumber/ or algae wafers (about 4 per serving ) even try mushrooms / some shrimp pellets occasionally and remember it will "hoover up" any left over food you feed the others too
HTH
mr pleco