Very pale body related to constipation?

One of my leucistic P. waltls went very pale a couple days ago. Her sister has always been a little darker, but now the difference is stark; the affected one (Gussie) is almost pure white instead of her normal pink. She's still eating, seems normally active, and neither the other leucistic or the wild type in her tank seem affected. I checked water quality and the only thing off was high nitrates. (I wasn't checking as often since I have a zillion plants in there, but that explains the algae bloom.)

I did a couple partial water changes the last couple days and everything is back in the ideal ranges, no ammonia of course! But Gussie isn't darker, so now I don't think that's the problem. I have noticed that while not floating or struggling, she does seem to be carrying her rear end a little high, and the tank is looking a bit overgrown, so it's extremely possible she could have swallowed some java moss or other plants while eating to cause constipation. Could that be all it is? I found one reference in my forum search to a pale axie that resolved after pooping. Gussie looks dark on her translucent sides, but not sure if that's what she's digested, or she's gravid again.

Anything else I should watch for or do? How long should I give her before drastic measures like fridging to induce pooping? (If that's even a good idea.) Up until now, Gussie has always been my biggest, strongest, healthiest newt!

BTW, she's a young adult, doing well on Hikari Carnivore pellets (semi moist). It's an established 50-gallon tank, and I think the nitrate spike was from overfeeding during my vacation last month, so should now be resolved.

Well, I believe Gussie has pooped, but she's still very pale. Sometimes I think she looks better, but then I'll see her looking almost yellowy-pale. Meanwhile, her sister Finknottle is even darker pink than usual. I'm always worrying they are too dark and veiny, and now I've got one too pale; I'm never happy. :eyeroll: If anybody has any input on variations in leucistic coloring that might be relevant, I'd love to hear it. Meanwhile I'm just maintaining good care, waiting and watching.

Here's a picture of pale Gussie on the left. She's a little sluggish but eating great, just so pale! I read inactivity does make them paler, but she used to be super active.

Better picture

Here's a better pic from today's feeding frenzy.