Neon Tetra Acting Strange Part 3

[confusion]

I'm not sure if this should go here or not. I have 5 remaining black neons. I noticed today that two of them were hanging out together in the center of the tank at the top. At first, I saw both of them tilting sideways and swimming erratically that has become a hallmark of doomed neons in my tank. Then I noticed that they only swam like that if those two were near each other. They apparently are not letting each other out of their sites. So, as one swims behind, above or below, the other tilts his body to keep it in sight. That's about as best as I can describe it. They are still actively swimming. I am not certain that they're eating, though, and both have somewhat faint black lines relative to the other 3 black neons I have.

Is that behavior some kind of spawning ritual or male domainance dance? Or are they actually sick?

 

[WILDER]

Sounds likie it could be a parasite to me, as they can tilt to one side with parasites, do you mean there darting around, any laboured breathing or flicking and rubbing against objects.

Darting
Water quality problems, skin parasites, drug side effects, stray voltage in the tank