Betta fish and birthday cakes

Tomorrow is my husband's birthday, and I have to say that I feel very well prepared for this event. His family wants to celebrate together tomorrow, so on Saturday I'm going to let him sleep in, play guitar, maybe take him to his parents to play some XBOX, then take him out to a movie he's been wanted to see. I'm pretty stoked. Plus I got him a gift that I know he's wanted since he moved in to the apartment.
I do have the pleasure of baking some kind of goodie for him. Some cake or other deliciousness. I am not quite sure what to make yet, but again, I am prepared for this.
What I am not prepared for, though, is the care and keeping of our two new betta fish. When I lived in the apartment alone I had two betta fish in one tank with a divider. (This is perfectly safe, by the way, just so long as the fish cannot touch each other, there are no negative effects). About a month or so after acquiring these fish, one looked decidedly lazy and lethargic. He wouldn't swim and make bubbles like his neighbor. Needless to say I was not surprised to find him belly up one day when I got home from work.
It was his neighbor's death that really upset me. I was in the habit of turning off the heat in my apartment when going to bed. This, apparently, is a terrible idea. One Friday this past December I turned the heat off as I left for work. As I was leaving work, snow was falling in larger quantities than I had seen it down in Virginia in a long time. My husband and I went out with some friends from work, and by the time we got out, the whole city was covered in a blanket of white.
Now most cities that get regular amounts of snow are aware that plowing is necessary for the city and its residents to remain functional. That is not true for the city in which we live. No plows or salt truckers were seen the entire weekend. Knowing this would be the case, I stayed at my then fiance's house, in case I couldn't get out of the apartment. By the time the roads were clear enough to drive on (Sunday morning), my apartment had reached 45 degrees Farenheit, and the poor lone Betta had frozen his little fins off.
And so today we acquired two new Bettas, my husband promising that he would be there to help take care of them. I'm terrified of killing more innocent animals for the sake of having pretty things to swim around. I've got my fingers crossed. Wish me luck!