large goldfish behavior from pond to aquarium

Question
I have moved two large goldfish from a pond into my 75 gal aquarium.. no problem moving them but they do not seem to want to eat. They swim every once in a while skimming across the water at record speed with their head out of the water and their tail down... vertical.  Is there something wrong with them?  I have an air pump going and a flugal x5 filter and leave one of the lids open for most of the day for air.  
My other fish koi are thrilled with them not going for the food.. Im not sure what to do.  Ive done water changes and im afraid to feed to much.  Please help

Answer
Hi Karen,

I encountered this often, during winter months.  If the water gets below 30, I bring mine in also.

Filtration - Goldfish need high, heavy duty filtration.  Two to three times what it's rated.  Four or five times wouldn't be overdoing it, imo.

For a 75 gallon tank, run enough filtration for a 150 to 250 tank...watch the fish become much more stable.  

The ammonia levels in goldfish water are going to be higher than normal, because they exhude waste.

Also, the rule of thumb is if they are over 4" long, then you can only house 1 per 7 gallons of water.  That means, for your 75 gallon tank, you can house no more than 10.

I sincerely hope this helps.

Renee