Humpback guppies

[guppymonkey]

So I have been looking up the different diseases that plague my guppies, and one thing I have never been able to solve is the Humpback Disease.
Info that I have found is that it is a vitamin D deficiency. They need more light?
http://www.guppies.com/index.php?opt...d=23&Itemid=36
Currently they sit in front of a window and have a T8 standard sun bulb.
Only some of the fish get it.
pH is at 8 or so, hard water, weekly water changes, all other test are normal or very low.
Only other fish are kuhli loaches and glass shrimp. gravel substrate, back filter, live plants ( java moss, anubias nana, najas grass, crypt.

Any suggestions?

[XanAvaloni]

Could it be a genetic thing. Guppies are pretty heavily inbred...

that page you linked too sounded a bit, um, odd....the ability to manufacture Vitamin D from sunlight? That I am pretty sure is confined to land animals, particularly mammals. Not a biochemist so I can't say for sure. But if everything they listed would "kill guppies" I would think the species would be long extinct by now.

[Dangerdoll]

I've had guppies that's happened to usually after a large birth but that seemed to be the only thing though... they just looked messed up

[jpappy789]

I'm also inclined to believe it's genetic.

[J double R]

In my experience, it's genetic. Guppies came along that had spinal deformities, and the guppies they gave birth to in turn had the same deformities, whereas normally formed guppies gave birth to the same.