Thinking about dividing a section...

[MegTheFish]

My ten gallon occupants are: 1 flying fox, 1 balloon molly, and 5 guppies. Its filterd (whisper HOB) and heated by a 50 watt heater. I want to divide a small section off for one of my bettas, using the dividers that you buy in lfs, not the home-made ones because then I would have to tear down the whole tank to do that (since you need to silicone it). The dividers are about $10.
The length of the 10 gallon is about 20", so I would take maybe 5" so then the section would be 5" by 10.3" by 9.1" with equals 3 gallons. Would this be an ok size or should I make it smaller?

 

[MegTheFish]

Went to look at the dividers, and they only had one for a 20 gallon high, so hopefully they'll get some ones for 10 gallons soon.

 

[MegTheFish]

Uggg....my balloon molly just died. Now I'm left with 5 guppies and the flying fox (but hey, more room for the betta!). But, I'm not going to be adding him any time soon, because this is the 2nd fish that has died this week, so I think something may be up with the water and I don't want to end up killing my betta, too. I'll have to test the water...maybe I'm not doing enough water changes ) But then again, I've never been able to keep mollies alive that long...


Edit: What? Is there a curse or something thats keeping anybody from posting?