Originally Posted by matfalk
just do a cold water change, and they'll do there business.
Geez... the one time that my Fiance is more difficult than my fish tank. At least the fish don't nag.
I tried the cold water change on my wife once. Didn't work. Counter-productive, in fact. I find that doing the water change on her with Vodka' Cranberry, and Grapefruit can induce spawning, though.
Sexing Cories: Hard to describe, easy to do. In a group of six cories of similar age, you are virtually guaranteed one female and one male. The males are wedge shaped, the females pear shaped, but that's kind of hard to eyeball. The easy way to do it is that the females will be 1/4 to 1/2 again as big as the males. Like I said - it's pretty obvious.
Breeding cories in a community tank:
Cories can spawn in a community tank, and I have successfully recovered some fry even when I didn't know they had spawned. However, it was a very small number of fry compared to the likely size of the spawn, (10 as opposed to 30+ from my last batch from 100+ eggs). That worked because I had a pebble substrate in most of the tank, and it was large enough that the fry could get down into the gaps between the pebbles and out of harm's way until they were too big to eat.
The last spawning, my albinos spattered eggs all over my 55, and there were enough of them on my java fern and giant sag that I could trim the leaves and put them in a dedicated tank. Used 1/2" of all purpose sand for substrate, and stuck a hunk of driftwood in there to soften the water. Fungus got about half the eggs, but I still got 2 or 3 dozen fry that have survived for 3 weeks or a month (some of them are big enough to chow down on daphnia now.) I had to leave most of the eggs on the glass in the main tank, though, and those were like the candy aisle in 7-11 to the tetras and plecos.
Your best bet is a dedicated 15 gallon tank with a 1/2" sand substrate, a half flowerpot for some overhead cover, and a breeding team of 6 cories, ideally 2 females and 4 males. Keep them in there, feed live and frozen foods, and do water changes to drop the temp 5-10 degrees every couple of weeks. Once they've spawned, remove them to the main tank and read Julie's post on spawning cories for great advice on baby raising (and you prob'ly ought to track it down and read it before attempting this in any case, and do some intensive googling. Some cories are pretty tough to breed, some really easy.)