[Cthulhu]

I see some grey pipes and I want to paint it black. No colors anymore I want them to turn black.
So what kind of paint can I safely use for PVC that goes in the aquarium?

 

[tekkguy]

Krylon Fusion is safe, but the paint may chip after a while depending on how much the PVC gets touched in the tank.

EDIT: You can probably keep it from chipping too much if you give it 3 - 5 days of drying time outside of the tank, and use several really thin coats.

 

[Jeffww]

I don't know if you can put a red door in an aquarium. But I second krylon fusion spray.

 

[Sake]

Couldn't hurt to lightly sand the pieces you are painting, that way the paint has a bit more bite.

 

[TonyK]

I have nothing to add but, I love how you started the post.

Paint it Black!

 

[talontsiawd]

Most people will recommend Krylon Fusion. I think it's a good recommendation as it's made for plastic. That said, any spray paint will be fine and I actually prefer using black automotive primer. I also think Valspar makes the best off the shelf, generic spray paint so that would be my second choice.