Sucking Loach Changing Colour?

[matty_022001]

Just wondering if anyone has ever had a sucking loach that has changed colour, I brought 2 standard looking sucking loach from a local petshop but when i got them home 1 of them went half yellow and now its nearly all yellow, If anyone else has had this happen please reply or if you know why this has happened please tell me cuz i think its strange. the attached photo is a picture of my large sucking loach which is what my yellow loach used to look like, http/s489.photobucket.com/albums/rr255/m...t=Photo0222.jpg

 

[Darth]

Are they both male? Do you have any other fish in the tank?

 

[matty_022001]

yea its basically a small communtiy tank with 2 angels, 3 mollies, the 2 loach, 2 bogwood loach, 1 red tailed shark, 1 sailfin pleco, 1 bristlenose pleco, 1 green phantom pleco, 2 unkown catfish, 1 striped rapheal catfish, 2 khuli loach, 4 spanner barbs, but the loach changed colour when i first had it as i said, he is still 2 colours but is only half gold now and has sill got a faint stripe from the middle to the end of his tail, obviously this picture isnt the one that changed colour but its a pic of the other one that didnt,