It's fine. Luckily, I've dealt with 10g sets ups, so I can help you out. Yes, cories can be put in a 10 gallon with a male betta. But, you don't need 4. That's too many. You'll be fine with 2. Also, cories don't breed in aquarium sets up, so sexing them is useless. Typically, only mollies, platies, swordtails, and guppies will breed in an aquarium. You can do them with a male betta too, but I'd stay away from guppies. Too risky. I fed my cories brine shrimp sinking pellets daily. Snails eat algae wafers. Again, daily.
Don't put a betta in a 10g that's being cycled. Good fish for cycling are mollies and platies. They're hardy, and can make it through the nitrate, nitrite, and ammonia fluxes. It's best to run the 10g for a week before adding fish, if you can. When you add the fish, add a bacteria supplement. It'll just make the process easier. Do a light load of fish. Around 3, 4 at the most. Make sure you have all males or all females. You don't want to do the cories during cycling. It will most likely kill them since they are bottom feeders and bottom swimmers. No snails either.
A 1/4 partial change will be needed once a week. I only changed my filter cartridges once a month, but I have a super good filter and the tank was cycled. I'd suggest biweekly at the least while being cycled, but someone else probably has a better idea of exactly how often it needs to be changed. It's been a while since I cycled a tank. And yes, you'll add water conditions for the 25% of the water you changed. And, I believe, a cycling tank needs a water change once a week. Once it is cycled you can do monthly if the tank load is light. I would do biweekly if the tank had a head load, like a betta, 2 cories, 2-4 other fish, and snails. If it's just a betta and corries and a snail or two, monthly would probably be fine. But, it depends on your filter. Once you're done cycling, test your tank often, every few days, just to make sure you can gauge when your particular tank needs its water changes.
The bubbles don't filter the water. It's more decorative than anything. It oxygenates the water some, but other than that it's a pretty effect.
As far as the light goes, turn it on when you wake up, and off when you go to bed, unless you have unusual daytime hours like 9a - 2a. I left the light on my aquariums for about 10 hours a day.
Last edited by coet; 06-27-2011 at 11:42 PM.