I have a friend who has bala sharks and he asked me this question because he knows that I have two...He asked what could cause one of them to get swollen eyes and that they are glazed over? I told him that I am no expert on fish, but I would certainly get him some help by coming to the place that has been here for me in the past to try to help him figure this out.

What are his water readings? They will react to toxins the same as any other fish.

nitrate- 80ppm
nitrite-0
alkalinity-180
ph-.78

he also asks why its only eccecting 1 fish and not the others?

effecting

What is the ammonia?

It can affect one fish, and not the others as they have the equivalent of an immune system. So one may have less tolerance than another.

i dont know he has those strip type testers and it only show 5 things
oops left out hardness-150ppm

could be many things, need accurate water readings ot be sure though.

glazed eye could be some kind of infection due to toxins in the water, or an infected injury.

or could be large because the fish is stunted due to a small tank...cant be sure of anything without accurate readings - thats means with a propper testing kit as those dip sticks aint really 100% at all im afraid

liltone09 wrote:

if the reading is correct, you need big water change a.s.a.p. 80 ppm
is too high.... water change won't hurt your fish if you did have wrong
reading,,,, but must do w/c to reduce it if it is true...

other fish may not be affected yet but soon it will.

Swollen and glazed over eyes is popeye, a bacterial infection. The 2 most common causes are fighting and bad water. You friends water quality is bad- the nitrates are far to high, 40 should be the max.

The best thing to do is test the water before a weekly water change and if the nitrates are over 40 then you need to do bigger or more water changes. Dont overfeed, only feed what they will eat in 2 or 3 mins

To cure popeye you need to get an anti bacterial treatment. Im in the uk and i use Myxazin. Follow the instructions and remove any carbon in the filter (dont bother putting it back, add more bio media instead)

Some fish are weaker than others and this is why one fish has it and the other doesnt