Peppered corys are tropical fish and probably wouldn't be very happy in a coldwater tank. Also, because goldfish are scavengers and dig through the gravel a lot, it would probably make the cory very nervous.
I believe weather loaches are also tropical, so I'm not sure they'd be the best choice for a cold water tank either. -- However I don't know much about weather loaches, so perhaps someone more knowledgeable can help you with them.
I believe hillstream loaches are appropriate for coldwater, but I think they require a fast water current. I'm not sure what other types of fish might be appropriate -- hopefully someone else can reply and help with that, or perhaps check the coldwater section?
What type of goldfish do you have? Is it a comet or other thin-bodied/fast-swimming goldfish, or is it a rounder, slower-swimming variety (like a ryukin)? That would possibly have an impact on potential tankmates as well.