I have a white coud that I've had since..summer 2001 methinks, maybe just before.
My mum started a ~ 4gallon betta tank just before we left on holiday, and he was one of the 3 white clouds to share this tiny tank with the betta.
Came back from holidays to find the betta dead and the water cloudy. We hadnt cycled the tank properly, just followed the instructions on the stress zyme, test strips revealed lots of ammonia.
The white clouds then went into my mixed goldfish/subtropical tank, and survived 'clem', the goldfish who ate about 10 neons, killed a moor and a fantail and tried to eat a corydoras before I rehomed him.
I added a heater, and swapped the goldfish for even more unsuitable catfish (2
S.decorusand 1
S.eupterus). Then after nearly a year our water pipes got changed, killing all my fish with from copper (I presume) apart from the 3 white clouds and the
S.eupterus (I think 1 zebra danio survived too). For a month or two they all lived extremly cramped in the 4gallon again while I tried 'maturing' the bigger tank using fish food and testing the water.
So yes, I'd say they are very hardy fish.
After that everything went fine, until one of the white clouds
died eating a pea.
The remaining two went in the
new tank just over a year ago.
I lost a second one just before christmas due to old age, but I still have one left.
His body is a bit crooked, his fins a bit taty and his eyes seem to now be perminantly cloudy, but he's still eating and seems pretty happy amongst my 10 zebra danios.
I'll try get a pic of my old timer later, would love to see your old guy, probably younger looking than mine

.