Strange black line on fish

[Deepseadivingforanswers]

One of my Cloudy Minnows has this black line curve around its internal stomach. None of the other fish from what I can see has it, it’s only noticeable when the lights on. It has also had a strange stomach shape for weeks now, and has this little white lump on its anus.
Ive attached a photo of as best I can get, also it looks more pale then the others. Is this normal? Does anyone else’s cloud minnow have the black line? Hopefully not an internal parasite. It could also just be a long poo maybe?

 

[A201]

I think the minnow is exhibiting a clogged "mud line". It's likely constipated. Might be a good idea to hold off feeding for a few days & hope the situation corrects itself.

 

[Deepseadivingforanswers]

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I think the minnow is exhibiting a clogged "mud line". It's likely constipated. Might be a good idea to hold off feeding for a few days & hope the situation corrects itself.

oh ok, they are little pigs when it comes to food. I’ll do that, thanks!