I had a few that were in the 8 year old range ..when I got out of the hobby 13 years ago. Then,three years ago got back in and around the one year mark back in a bought like five small clown loaches. Two died over a few months time,the last three have been happy and healthy and grown from the 1 1/2 inch size to over 3" right now..maybe 3 1/2? and with stout bodys. They are active and in the morning the trio swim back and forth along the front glass (8 foot long aquarium) like they are swimming up river for a few hundred yards. I've seen them even get right in front of the return pipe from a 1,200 gph pump and that's when you see that these are river fish..powerful swimmers.
I think they are very healthy..but might have grown larger if I fed live worms as I would do years ago. Still,shrimp,krill,color flakes and beefheart is the rotation.
Clown Loaches are a must have for me. I do have a Queen Botia that's' over 4" but doesnt have near the looks or personality of the Clown Loaches. The Queen is also more nocturnal then ever..the reverse of when it was young and small and out in the day.
I might add more Clowns one day..but only if I set up a quarantine tank for them. No more,just plop fish into my settled tank these days. Never take the chance of a wipeout.