There is some tension between keeping fish as the most perfect specimens possible, and keeping pets to whom you have a lifelong commitment no matter what happens to them. Aquarists tend to straddle that divide. For example, I keep colored ramshorns snails and I like them well enough, but I do not know them as individuals and I ruthlessly "squish" excess snails to prevent over-populations. I feel no particular obligations to the individual snails and keep them mainly as specimens and "decorations".
And then there is Paff.
You can get a Fathead minnow like Paff at a local fish store for around ten cents, they are used mainly as feeders and bait fish. I got Paff as a pet, but she escaping the usual fate of a minnow did not put her on easy street. After a slight injury she developed a serious infection which caused swelling in one eye (an effect called "popeye" or "pop eye"). It didn't respond quickly to treatment (Maracyn and water changes) so I thought it would be humane to euthanize her. But she was hard to get out of the tank and thrashed around in the 1 gallon jar, demonstrating plenty of health vigor and quite the temper.
She recovered from that and continued as normal, beating up the other minnow and claiming the cosiest spot in the tank. Then the infection reoccurred, leaving her totally blind. I took her out again, but again she seemed otherwise healthy and now infection free.
So, Paff is not the prettiest or even the healthiest of fish, and she has at least one obvious defect (no eyes). However she has quite the bullish personality and a good body condition. I make sure to drop food near her and put a little fry food in the water from time to time and she seems to do very well. She seems to get around the tank well and rarely bumps into things, and she is still the boss of every fish in the tank, including the much larger male Fathead (called "Bubba").
So, not a specimen, but definitely on of my favorite pets.