Hillstreams changing color and pattern?

[Setsuna]

Hey there, in my other post "Hillstream/borneo/butterfly loach" I described the two new hillstreams I bought.

I noticed today that the larger one (with the striped top fin) has changed color. Its formally white spots and stripes on the top fin have changed into a vivid blue (similar color to the "author/message frame above this message)!

Also, the smaller one while still having spots on its fins, has now got horizontal stripes accross its back.

They look like this no matter where they are, on the glass, driftwood or the gravel. Unfortunatly I dont have a camera to be able to post images up here.

Can anyone determine why they would change color and pattern? I have not added anything new to the water nor done a waterchange. Ph is 7 temperature is 28 (celcius) very low ammonia, nitrate and nitrite levels (they dont show up on any of the tests, I did 3 to make sure).
There are live plants, and they seem to be in good health.

[William]

Sounds like they are settling into your tank and the reduced stress, better care that they get in your tank compare from the store is giving results.

[Setsuna]

So in other words, I'm doing something right and shouldn't worry. Thats a relief, thanks

[William]

Haven't seen any pictures but yes sounds like it ;-)

[A.J.]

I have a Hillstream Loach that will change to a very dark mottled pattern if sucking on to the filter (which is black) and the change to a light brown/green when on the gravel on the bottom. I was very excited when I first noticed this behaviour as I didn't think they could alter their pigment. Nothing to worry about!