Hello. I have a lone Zebra Danio that I got 4 years ago when I set up my 1st 55 gallon tank.I got 9 immature zebras to cycle the tank, and there's one lone survivor of the 1st bunch of fish I got. Is 4 years a long life for a zebra, or any tropical fish? I'm curious as to the ages of some of our members fish.
