Well done Viktor you are somebody I look up to and admire. You show your triumphs and occasionally failures so we all learn. Its a fascinating project you share with us.
We don't often know the normal lifespan to be expected because the data is hard to come by.
I know a bit about Clown Loaches. Most Clown Loaches don't die of old age. They die of neglect, Whitespot/Ich, tank leaks, heater failures, filter failures and a hundred other causes.
Owners of old fish often didn't get to find out how old their big fish were at purchase time.
Even though mine are 30 years old for certain, it seems that this is not a normal expectation. Most old Clown Loach deaths reported to me were in their early to mid 20s. I know of one other 30 year old still alive whose owner I converse with and one that died aged 32 in 2018 whose owner I discussed it with.
A billion Clown Loaches have been exported officially (with paperwork) from Indonesia during the period I have had mine.