What is too deep for wintering?

[jbherpin]

I have a large tub containing my notos. They are in the garage for the wintering proccess. Right now the water is at about 1 foot deep. It has water hyacynth (that I expect to die off), duck weed galour, and java fern. The bottom is sand, with a few large rocks strewn about reaching up toward the surface. The tips of 2 rocks come within 1 inch of the surface. I am using a sponge filter and it bubbles pretty good... I have a few questions...

1. How deep should the water be?
2. I want to avoid freezing, is an airstone enough to keep from the top from freezing over?
3. They are WC, (only 2 -a male, and a female-) and have experienced very low temps. The lake they come from freezes over very thick, and people ice-skate on it. What is the minimal time I will need to keep them outdoors to stimulate breeding readiness? I thought maybe 2.5-3 months...Is this enough?
4. How often should I drop in worms at this time? I don't want the worms to die, and foul my chemistry!

Any thoughts are greatly appreciated!

-jbherpin-

 

[Greatwtehunter]

1. Sixteen inches seems to be a good all around number. The water stays a more stable temperature this way, especially on those few warm winter days.
2. The air stone will keep it from freezing over but it won't keep it from freezing from the bottom up. I set my tubs on styrofoam sheets to combat this problem.
3. For me it seems around two months below 50F does the trick, the closer to 40F you can get the better.
4. I feed them once a week mostly but then during the coldest parts I drop the feedings down to once every two weeks.