Which symptom is common in fish suffering from swim bladder disease?

Swim bladder disease primarily affects a fish's ability to control its buoyancy, which is facilitated by the swim bladder, an internal gas-filled organ. When a fish suffers from this condition, it often experiences difficulty maintaining its position in the water column, leading to buoyancy issues. This can manifest as the fish floating to the surface, sinking to the bottom, or having trouble swimming upright.

The other options, while they may indicate different health issues in fish, are not directly associated with swim bladder disease. Inflated gills may suggest respiratory problems, visible lesions on fins could indicate infections or injuries, and faded coloration is often a sign of stress or poor health not specifically connected to buoyancy control. Consequently, the symptom of buoyancy issues is a hallmark of swim bladder disease, making it the correct choice.