Hi,
I have a tiny female betta and I change her water just about every day (she's right at the sink and I had been feeding her BBS but now she's on BioGold). She continues to have a slimey film over the top of her water. The water is clear and clean looking otherwise. She's in a half gallon vase (not her permanent home but easiest considering what she was eating). I have other bettas (6 males) in one gallon jars and they go 5 days or so between water changes and they never have the slime.
I have a tiny female betta and I change her water just about every day (she's right at the sink and I had been feeding her BBS but now she's on BioGold). She continues to have a slimey film over the top of her water. The water is clear and clean looking otherwise. She's in a half gallon vase (not her permanent home but easiest considering what she was eating). I have other bettas (6 males) in one gallon jars and they go 5 days or so between water changes and they never have the slime.