I'm going to guess it doesn't even look old. I say that as I have clown loaches, a silver dollar, two synodontis, a stripe Raphael cat and an ancistris, all nearly or just over 30 years old. I also have a botia striata that is just behind and it's the only one that shows any signs of aging really. Most of the other fish I had with them lived 20-25 years as well and I think it is possible with stability, minimal changes (like not moving the fish or adding any/many new ones) and plenty of luck.
I think my point is that lots of our fish can live for far longer than we envisage unless we come up with inventive ways to kill them off early, or they come up with their own ideas. I dont think i habe done anything special, just water changes and decent food.
When I looked into many of the species listed above I found that some seemed far longer lived than average but others potentially have a way to go. The Raphael for instance is about 20 years behind one I saw in Berlin.