my silver angel hasn't eaten and has just been hanging out in one place for the past two days, today, i put him in a hospital tank but his stomach is concave and he won't eat, there are no worms or anything coming out of him and he looks and acts perfectly healthy except for not eating or moving a ton, water is at 0 ammonia, 0 nitrites, 20 ppm nitrates, soft, 160 alk., and 8.0 pH, what could be the problem?
thanks
thanks