60 - Old enough to remember:
Putting a copper penny in a fish tank to prevent disease.
Never doing water changes or stirring up the gravel for fear of methane gas rising and killing off the fish.
Old metaframe aquariums with stainless steel edging and slate bottoms.
Fish being sold in 5 and 10 cent stores.
Lots of Mom and Pop fish stores.
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I must be getting old. I forgot the rest. LOL!
Oh yeah, the 20 gallon tall slate bottoms tanks, where the stainless metal frame actually got thicker down near the bottom of the tank. The bubbler corner filter filled with white cottony material or even better an under gravel filter with bubble risers on each side.