hey just wonderin if anyone can tell me how long it takes for a clown loach to reach maturity.

Now that is a tough one. Clown Loach can live for a very long time, I've heard people mention of up to 80 years. Since these fish are virtually impossible to breed in captivity I couldn't tell you for sure when they become mature. It may be a case that these fish like some other fish don't start reproducing until they are several years old.

I know that when I had mine they barely grew 1 inch a year so my two seven inch loach were probably quite old I would imagine

Keep your water quality good, and you might get them to 4 or 5" in a year but like OFL said they can live up to 80 years so and they do grow slow, thats why the larger ones cost so much

as ofl says there isn't a lot of solid information on these fish. my largest clown seams to have stopped growing at 8" the others are very very slow at catching up. i would say if you want a fully grown clown, pay the cash and get a large fish as growing them is slow. this has a little advantage as it means you can have a few in a tank for sometime before needing to upgrade.

what is your specific question.... when was a loach considered and adult
or what size a loach can be considered an adult????? i was told that loaches
and red tail shark are considered adult when they are about two years old...
irregardless how big they are.... so if you have a 2 inches long loach age
2 years old, then it can be considered as adult....small adult...

Clown loach grow very very slowly indeed. If you see one that is 6 or 7 inches long then it is probably at least 6 years old.