Is 5.5 gallons enough for two Bettas in a divided tank? Probably one male, one female.
technically yes, though some people frown on them being kept in "small" spaces like that. I currently keep a single male in a 2G goldfish bowl and he seems fine with his space. make sure it's filtered and HEATED.
I guess Id use a small sponge filter in one of the back corners and a small clip-on light bulb. Few Silk plants. Would this be good?
i would personally use a sponge filter on each corner, as you will have (i'm hoping!) a divider in the middle and the sponge filter wouldn't be strong enough to filter the other end of the tank/bowl through the divider.
if you weren't planning on having a divider, then GET ONE. you can not keep a male and a female together just as much as keeping two males together. this is only done for breedind [after they've been conditioned!
P.S. Do Bettas jump? I have a screen cover for like reptiles, if they do can I just use one of these?
everyone has told me that they do. i've had two (the one now and the one that it replaced) in an uncovered bowl for 3+ months and they've never jumped. however, taking into account just how many people say they are jumpers, i have my 10G male divided tank covered with a nice lid. it's just not an option on the bowl due to the shape and such.
I would highly recommend you put the screen on, just make sure it's got holes for air to get in