my kuhli loaches keep some squeezing through some holes in my filter and because of them being kuhlis they are too hard to catch out again. most of the time i have to scare them out. but this is hard is there a way to stop this?

I have heard of fish surviving in filters for quite a while. I actually had a female betta that loved to hop up into the tiny air-pump-powered filter in my 2.5-gallon to just hang out... maybe for the oxygenated water? Anyway, I found a tiny HOB filter for that tank so it solved that, but what kind of filter do you have? Wrapping panty-hose or some other kind of really fine mesh around a filter intake can solve problems like that.

just buy a sponge cover for it.

Very shortly after I started fishkeeping I had 3 kuhlis in my 16gal. They were still very little but it didn't take them long to grow and one of their hiding spots was an anemone decoration with a hole at the base where the purchase tag was looped into.

I noticed after awhile that one of them had disappeared for a couple days and after some investigating I pulled the anemnoe decor up and saw him - decapitated.
Kuhils are very good at sneaking into very small hiding spaces but this one obviously didn't know his limits. He got into the hole but wasn't able to come back out.

Get a sponge intake cover as jweb suggested or get some nylon stalkings and cut a small piece out and wrap it around the intake with a rubber band or something. There must be some very large gaps in your intake for a kuhli to get in or they're just babies..

lol check your filter!!!!!!!!!! and under rocks because of my experiences with my two striped ones and black one they hide although even though regarded as "NOT" as attractive as the striped version the black kuhli's seem to be more human friendly LOL hope he's alright , J