I have noticed the same behavior in rtc. When ever they are moved from one tank to another, it takes them time to acclimate. They are quite sensitive to cahnges in water parameters. I have experienced this from moving these cats from other tanks into my own, from my tanks into other peoples tanks, and even moving them within my own system. In fact these cats generally don't even eat when first moved into a new environment. The fact that yours is eating, as previously mentioned, is a good sign. Also remember these fish are not very active during the day or when they are full. If you are feeding everyday, spread out the time between feedings. My cats are active at night and extremely active, nearly jumping out of the water when they are hungry! My big rtc ~22" took about 7 days to get used to the bigger tank, but he still sits around in the same place, next to his favorite piece of drift wood. Check the conditions of the water, i have found they are more quirky about ammonia and ph than nitrates/ites.