A few days ago I noticed one of my two fantail goldfish wasn't eating the food I was feeding them. He kind of chase it around but couldn't get it into his mouth. Then I noticed there was something wrong with his mouth. Its deformed... its like his upper lip is gone or has caved in or something. When he opens his mouth the bottom lip opens normally but the opening is too small for him to take in any food.
I've been feeding them Tetra Goldfish Crisps which they love but the pieces are too hard for the injured fish to take in. The other fish gobbles all the food before the injured one can get any. I bought some flakes and it seems he is able to suck the smaller pieces in better. Other than his injured mouth he seems to be swimming around just fine.
I really don't know what to do for him other than just keep the water clean and feed him the flakes....
Can anyone here offer any suggestions?
Aquarium is 10 gallons.
Had it for about 3 months.
I have two fantail goldfish (about 1.5 inches each).
No live plants.
Water is 23 C (room temperature)
Using an AquaClear 10 gallon filter (Sponge, Carbon and Biomax Filters)
Tank receives diffused sunlight for most of the day.
Weekly water changes of 25%
Tetra Goldfish Crisps twice a day.
A single flourecsent lamp in the tank hood is on for about 3 hours each evening.
Ammonia=0, Nitrite=0, Nirate=5ppm (API liquid test kit, not strips).
Bought the last fish about a month and a half ago, no unusual behavior unitl recent.