I brought home 2 zebra danios last week to make a school of 6 that live in my 10g tank with my betta.
One of the 2 was a BIG female who looks gravid as all hell. She also seems to constantly be breathing/chewing. Otherwise, she seems perfectly healthy. She's been in my tank for about a week now. She schools, darts around, eats ridiculous amounts of food (she steals from everyone, including my betta).
I'm wondering if she's got something wrong with her or is she just stupid? :P
The rapid mouth motion is what concerns me most.
Water parameters are fine. Tank is filtered, heated, lit and has the ability to be aerated too but I don't keep that on but maybe every other day for a couple hours. It has several plants including a java fern and a few clumps of mondo grass. I want to plant more.

Good idea, bad idea?