I am not aware of very much truly reliable information about the life spans of various fishes in aquariums. Much of the reported “data” is anecdotal and far from scientific. That fishes get older in the aquarium, where there are no predators, than in nature is undisputed—but diseases and mistakes made during care may shorten their lives. Information about age can therefore only be a point of reference. Among catfishes, a life expectancy of 7-12 years for Corys is normal, but for bigger catfishes 10-15 years or more is not unusual.
To research the maximum possible age for a Bristle-nose Catfish was certainly not the reason I set up a small 10-gallon (40-L) aquarium for my two children in the fall of 1984. We did not have much space, but the motivation was clear: nature was important for the kids. A few Guppies and two young Bristlenose Catfish (Ancistrus sp.) were added. They had hatched in the spring of 1984, and came via my brother-in-law from a colleague at work. Actually, we were very lucky because they became a pair; however, for many years they mostly avoided each other. This small aquarium remained their home until the turn of the millennium. The tank was furnished with a glass tube from an old filter, a small root for grazing, a few rocks, Cryptocoryne, small Sagittaria, and dwarf sword plants. The male set up his territory around the glass tube and the female dug a shelter under the root. There were even two feeding areas.
I cannot be 100 percent certain, but I don’t think they have ever spawned during this time. Perhaps the small aquarium did not meet their size requirements, or maybe the care conditions were not optimal (I only took the time to become a full-blooded aquarist in later years).
Anyway, all that changed in 2001 when the two catfishes were moved into a new 20-gallon (80-L) tank with more space, more hiding places, perhaps more complete nutrition, and regular partial water changes of about 3-4 gallons (10-15 L) per week. Since then, they (or, more specifically, the male) have raised one brood after another, and in 2006 both catfish still looked good. It really seemed as if they had been saving their life energy for their golden years.
Then, in the fall of 2007, I found the female dead in the tank one morning.
She was more than 23 years old. After some discussion, we decided to get a young female for the lonely male. Apparently this mobilized the male again, and a few months later he was back in his cave, fanning the next brood.
Until this year, I could not complain of a lack of Ancistrus fry-in fact, at times I found it tough to accommodate all the young catfish. But in early November 2012, the old male’s health went rapidly downhill, and his life ended—after 27.5 years!