Swordtail behavior question

Ok... Have a male swordtail acting weird... he is in a planted(fake)
45G tank, water is normal

pH 7.0 (was 7.6 a few days ago)
Kh 3
GH 6
Amm. ~0
N02 ~.25ppm
NO3 ~20 (~10 a few days ago)

Last water check was Thursday, water stats then were the normal
baseline for this tank. Saturday a three clown loaches were added to
the tank.

Friday rolls around, and we notice that one of the swordtails has
migrated to the bottom. This is a fantailed swordtail we got from the
Lyretail tank at the LFS a couple of weeks ago.

His color is normal, his dorsal is still held high, he appears to be
hyperventilating a little, and is belly to the gravel. He has moved
around a little bit, but has not left an area about 5 inches long by 2
inches wide under some plants next to the side of the tank.

Other than his gill action, and his lethargic hiding under the plants
next to the glass, he appears normal.

Any thoughts??

TIA

Tony



http://boyleclan.us/albums/fish/fantail_001.jpg
http://boyleclan.us/albums/fish/fantail2.jpg
http://boyleclan.us/albums/fish/aquaria2.jpg
http://boyleclan.us/albums/fish/fantail_001.jpg
http://boyleclan.us/gallery/fish/male_swordtails
http://boyleclan.us/albums/fish/standoff.jpg
http://boyleclan.us/albums/fish/surface.jpg
http://boyleclan.us/albums/fish/swordtails.jpg