Hmm, I think I remember reading they could grow to about 18 inches or somewhere around there?
A foot if you give them a big enough tank, a lot of people that have sucesfully kept clown loaches keep them in 6 foot tanks or more.
Most clown loaches only grow 15 cm in home aquaria because of unproper tanks
I dislike snails because most of the time there are no leftovers for them in my infested tanks which means they eat my plants, but if I got clown loaches that would not be a problem because the loaches would have already uprooted and punched holes on all the plants LOL.
There is this youtube couple that have a 75 gal and apparently did not research well enough, they are just finding out clown loaches LOVE to destroy plants, their tank looks great, but it will stop looking great soon...