Golden Endler livebearer with white spot
 

I just noticed this white spot on my livebearer today... It's huge, looks like it's part of the skin and slightly irridescent when I shine a white LED on it.

Is this ich or some normal coloration on my guppy?

possibly pregnant!

:O
 

possibly pregnant :DD if its on the belly side. its hard to tell

I broke out the camera and tripod to get a better shot. The white spot is on the dorsal fin and I'm pretty sure it wasn't there yesterday or two days ago. It's smooth and not fuzzy or bumpy, unless you count the patterning of it's scales as bumps.

My LFS told me that it was a male, though it's colored differently from my other two and it's a bit larger.

Right now, I'm concerned it might be ich or saddleback columnaris, so I'm going to get my tank params.

It's a heavily planted tank, so I expect everything to read 0, but I had an otto cat die yesterday within 24hrs of finding it lying on it's side.

Tank parameters
Housing
What size is your tank? 20G long
What temperature is your tank? 79F
Does your tank have a filter? HOB, with no charcoal
Does your tank have an air stone or other type of aeration? Just added one on 1/2/12
Is your tank heated? Yes
Inhabitants? Betta (1), Otocinclus (4), Assassin snail (2), Gold Endlers(3), lots of Malaysian Trumpet Snails

Food
What type of food do you feed your fish? TetraColor Granules
How often do you feed your fish? Twice a day

Maintenance
How often do you perform a water change? Never, it's a soil-planted tank
What percentage of the water do you change when you perform a water change? Never, it's a soil-planted tank
What type of additives do you add to the water when you perform a water change? Added StressCoat+ for the betta's fins

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia: 0
Nitrite: 0.25
Nitrate: 0
pH: 7.2
Hardness (gH): 0
Hardness (kH): 40

I was just looking at the dorsal and it looks a bit iridescent. Could that white spot be coloration. I have a video of one my black bar endlers and he has a white spot and the color goes into the dorsal. I'm thinking the fish might just be coloring up?