Greetings! I am new to the saltwater tank world and already having an issue my 3rd week in. My 55g tank was setup by a professional service, along with adding live rock, Dr. Tim's to the water (to help the cycle process) and two clown fish on Day 1. Bigger clown fish (Marlin) died on day 3 and the smaller one (Nemo...original right) just kept to one corner of the tank afterwards. Both were very active and eating at the time. My last remaining clown fish seemed to thrive for several days after and eating regularly. Now, we are on day 5 of no eating at all, just watching pellets pass by. No white spots or heavy breathing, just keeping to a very small section at the bottom in the sand. Fish professional not coming back until 5/18 to test, service and possibly add more fish. I am concerned he won't survive at this rate. Any advice to a saltwater rookie?