My fish floats but is alive and well.

Question
Hi,  
We have 6 fantail goldfish in a twenty-five gallon tank.  After we feed them, one of them will float to the top of the tank, like he has swallowed an air bubble or something.  Speckles (his name) will try to swim down into the tank, but every time he stops, he quickly floats to the top.  But he keeps trying and trying.  After a while, he just gets tired and simply floats around the tank, most of the time with his stomach at the top, meaning he's floating around upside down.  
One of the other fish, Chloe, also has this problem but to a much lesser degree.  After a couple of hours, he's fine and swimming normally.
I feel bad for the guy because he looks exhausted when he's floating around.  
Is this dangerous for him or is there a serious cause for this?  If there's no harm to him, I'll do nothing but I wanted to make sure.  
Can you help?

Answer
Hello Mike-

It sounds like your little ones have swim bladder problems - This is very common for fantails. When they eat, they tend to swallow at lot of air while they are at the surface. If you are feeding them flake food, try switching to a pelleted variety (or push the flake food under the water so it sinks,) this is thought to decrease the chance of the fish swallowing air because they spend less time at the surface. Another trick you could try is to feed your fish a defrosted, frozen pea (squeeze it out of its shell first.) Adding a few veggies to their diet can really help with digestive problems.

Swim bladder disease is rarely fatal by itself; as long as your fish seem otherwise healthy, this should not endanger their lives.

Hope this helps!
Amber Worman