my rtc got a gill parasite 2 weeks ago but has since been cured, water has 0 ammonia and ph at 6.5 to 7. the tank is 250 gal and he is about 16 inches long, he hasn't eaten in 2 weeks, he made an attempt to eat about 2 days ago but didn't eat how can i make him eat? he hasn't lost any color and and still moves around but im worried about him what should i do?