That's all it is and this is what got Prince down, he had one black tendril that turned into multiple problems and I've found the same issue affecting my white delta, Cinderella. I don't know if he got it caught or it's stress but my EE Elliott who shares the same tank looks like he has the symptoms of melt rot.
I just .. Blah.
Tank things are normal the only changes are their tails.
They've only recently been cleaned, they get fed once a day with 3 pellets, it's too early to test the water but it should be near perfect like it always is. They're eating, they're being normal and nothing is bothering them it's just their tails that bother me. ;.;
They're on salt at the moment.