Did you see the fish eat or did the guy at the LFS say it was eating? These fish can easily go a couple of weeks before they eat-- If they eat. Once eating, they are the easiest fish I keep to feed. The big problem with them is getting them to START eating. Try a fresh, opened clam from the grocery store, if that doesn't work; just hope he starts to eat what your other fish are eating. BTW, there seem to be a lot of people who consider Idols to be herbivores, they're omnivores. IME, they are more likely to eat meaty stuff as a first food than veggies. There is a very real chance that this fish will never eat, its the biggest risk with them and why they are considered one of the most difficult fish available. The "white spots'' are a whole new issue that you need to look at. Its very possible, by not using a QT (where its easier to get any new fish eating, IME & IMO), you may have introduced a parasite into your DT. Your profile says you are a beginner, please slow down and do some research; or you'll leave this wonderful hobby before you get started. Any source would have told you the Idols are anything but a beginners fish. BTW, can you tell us your tank size and present fish?.