New Goldfish Sitting on Tank Bottom

Question
I bought a new Koi less than 24 hous ago to be a companion to my large 4-year old goldfish. I am concerned beacause the new goldfish is sitting in one place on the tanks bottom for at least the last 13 hours and has not yet eaten. My tank is a 40-gallon with a Bio-wheel internal filter and an Eheim eternal filter. My nitrites, nitrtes, PH and ammonia levels are all completely normal. When should I start to worry...Is it possible although completely docile my 4-year old goldfish is too large and the other one is terrified? He is 4 times larger, but has left the new little guy alone, swims close but does not bother him?! What can I do to help this Koi swim and eat?

Answer
It can be fright or it can be a sign that you purchaed an unhealthy fish. treat you tank with anti parasite soultion and watch the koi closley over the days. also try other foods, ask the shop what they were feeding their koi and ask them if their supplier is reliable for great health fishes.