My what I assume is an Oranda goldfish, that I got at a petstore that claimed he was a Pearlscale goldfish, lives in a 10 gallon tank with a piggyback filter purchased from nooppee, it is meant for a 20-30 gallon, because when I first got him.. that's the only tank I had but it didn't have lighting, so he was then moved.
Well, the last water change was on Wednesday. The PH is at 7.3, nitrate, 0. nitrite, 0. ammonia, 0. the water hardness is soft.
He is only being fed a straight diet of Tetrafin flake goldfish food. (I didn't know much about my fish, only knew he needed good water conditions, light, and food, etc. basic stuff -- I recently did A LOT of reading..) a few days ago I tried feeding him, and he was sitting in the corner, I put the food in and he only got a little nibble and then when back to his corner. I looked up goldfish lack of appetite, and the only diseases I could find with those symptoms were TB and constipation, he didn't show any of the symptoms for TB that I saw, so I suspected it was Constipation, because his belly looks a little round. I am stopping the feeding for two days, this is day two.
I made some gel food with a recipe from Dataguru, and my fish after a little bit became aware of the food. He swam around, trying to find it, nibbling at the pebbles, but didn't get it.. I moved it to the spot where he kept looking in, and he hasn't gotten it yet, last I checked he was in the corner swimming in place..
Okay, I hope this information helps?