Golden Dojo Loach Changed Colour

[highlandloach]

Hi folks, I have a curiosity that I hope you may be able to advise me on. I have a Golden Dojo Loach who over the last few days has almost completely changed colour. We've had her for 2 years and the folks who gave her to us reckon she was 2 -3 years old at the time, she's around 6-7" long and quite meaty. We have 2 other golden loach in the tank who both appear to be fine. Mind you so does Bertha apart from the colour change. Is this normal or some crazy diseese I should be worried about do you think?

Aquarium details as follows: -
Tank - 90 gallon
Filter - biolife
the tank is decorated with live plants and bogwood with gravel and sand substrate.
we have platis, rosie and tiger barbs and a few tetras. (all small fish, the loach are the largest fish in the tank)
I do around a 40% water change every 10-14 days and clean the filter once a month.

I only use tetra sticks for checking levels, but all looks to me to be fairly normal for my tank.

GH - 30
KH - 40
PH - 7.5
NO2 - 0
NO3 - 20

Photo attached (I hope). She's a tad camera shy so appologies for the poor shot. That's her hiding under a piece of bogwood. She always had a couple of darker patches on her flanks but this is a very dramatic change.

[highlandloach]

I managed to get a better photo

[mickthefish]

youwere given an algae eater not a dojo loach highlandloach, it does happen sometimes that you get the mottled effect usually they stay this colour and never revert back to golden.

mick