How many days is a fewSimply dont offer food for a few days and then try to feed.
You should be worried right now. Look up on google how to perform a fish-in cycle. And okiko is one of the most problematic foods imo. As mentioned switch too hikari or better northfin or new life spectrum. A fish in cycle is going to be time consuming (every other day or even daily waterchanges and daily water tests) and much more attentive then just cycling your tank prior to getting the fish but it's the price you have to pay for not doing research beforehand especially for such an expensive fish. I hope it works out because your flowerhorn really is a beauty. Your fish not eating is the least of your problems right now. That's just a symptom to an uncycled tank. If not done properly your fish could have permanent damage or even die. Don't worry about feeding right now. worry about getting your tank cycled.When should I be worried