Goldfish Sudden Swimbladder Onset

[Jimmy8]

Our lone 8ish year old goldfish suddenly began hanging out on the bottom of the tank. This occurred soon after a routine tank/filter cleaning. 1 fish in a 30 gallon tank. Prior bouts of apparent swimbladder issues, though not on the bottom of the tank, have been successfully treated with peas. Is a broad spectrum antibiotic from Chewy likely to help? I’m open to the thoughts of more experienced aquarium keepers.