Here is a photo of my Coolie Loaches, well, about half of them anyway. They like to hang out in the little rock cave that I made for them. I bought half a dozen new ones last weekend. You can see that they are only about a quarter the size of the 2 that I have had for a couple of years. Here you can see the front 1/3 of one of my old ones, and a several of my new ones. 
Hey about how fast do they grow? Mines are about the same size as your new ones. But I can’t wait until they grow thick enough so I don’t have to worry about them swimming up the filter. Some of my other fish grow pretty fast, like within weeks or a couple months. But I’ve heard kuhli loaches are slow growers?
Serg they don’t ever really get all that thick. My last one from this batch just died this spring. He was longer, a bit bigger, but they stay pretty thin. I’d moved 4 times, had him in 2 different tanks, and I think he was the last of them. I’d never had filter problems with these guys, but I run filter gates from small filters even on my larger filters.
If you do have problems maybe zip tie a fine plastic mesh around the filter. Maybe the bag from a baby-bell cheeses? I think those are pretty fine.
Thanks Mike, I really appreciate the info. Sorry to here about your kuhlis…… I will def try out the cheese mesh bag, thanks for the idea. About how long did that batch of kuhlis live for? And how long did it take for yours to get to the size of the big kuhli in your pic? Mines are about the size of tiny ones in your pic. But your older kuhli looks huge (almost like the size of a small/medium size dojo golden loach).
I am looking at 8 years between the blog post and when I lost the last one. I don’t think I’d bought any more between now and then so it could very well have been the little one in the photo.
I love the Coolies, but I’d go 6 months between seeing them sometimes in a different tank arrangement. Having the cave ‘face’ a darker corner of the glass really helps with seeing them. As do having several.
The big ones in the photos would probably be 4-5 years old.
There are a few different varieties sold as Coolies, and I suspect I ended up with 2 different varities – there are some subtle differences between the big ones and little ones.
These guys can be hard to find at pet stores, but when you do find them, they are pretty cheap!
If the cheese mesh is too course, the plastic ‘loofa’ bath scrubs may be just the ticket! Some are sold with soap built in, don’t use that one, soap is bad bad bad for fish.