All high end expensive flowerhorn food has high concentration of astanaxin ( excuse my spelling) red algie, i only mention fh food cause of the extreme cost for low quantity but extremely high carotine quantity, you can buy this red algie and add it to your food instead of buying the high cost stuff.
Fish food marketed for FH is no more high end than any other decent quality cichlid formula on the market, which all contain one or more forms of astaxanthin. Speaking of which, astaxanthin comes in many forms, some are natural forms, such as Haematococcus pluvialis (a micro-algae) and phaffia yeast, others are synthetic products, such as CAROPHYLL® Pink, which is also used in commercial aquaculture. (salmon farms, shrimp farms, etc) Most specialty FH is overpriced to the extreme. Even a low quality mediocre fish food can give great results in color, all one needs to do is add enough synthetic color enhancing agents. Color is only one part of the equation, and the color red is the easiest color to produce via enhancing agents. The tricky part is using enough to enhance a red fish, without turning a fish that is naturally yellow, orange.
muscle ........ As clockwork stated, there is a 4.5mm floating pellet (Jumbo Fish formula), also a 7.5mm floating pellet (Extra Large Fish formula), and a small 1mm
semi-floating pellet. (Surface Feeder formula) I've fed all 3 formulas over the years to various cichlids, including FH. It's difficult to make a
small floating pellet (under 3mm) without using a fair bit of starch in the food, which the owner of New Life refuses to do.
I'm still scratching my head over how a simple question about pellet sizes can end up turning into a 9 page discussion. lol