Turtle shell problems?

[Meghanspood]

I cant find a turtle forum yet that will allow me to attach images, but Ive had these guys for around 7 years now and never noticed this. looks like red lines between each of their scutes. ones is a eastern painted turtle and the other is a RES. doesnt seem like shell rot or septicemic from what I have seen. activity levels and appetite are still normal

 

[The Snark]

I held off here hoping somebody knowledgeable would speak up. You need to talk to an expert and not a self proclaimed person who once owned a couple of turtles. Preferably a herpetologist with experience in testudines. Might be serious, might simply be aging or a common reaction to a mineral in their food or water or similar.