that tomato plant just didnt get to the stage of flowering, thats why it never grew tomatoes hehe ^.^
and dont add the minnows in with your betta, they need different water temps, you cant forget that many species simply cant be stocked together because of their individual requirements
like I said goldfish are a no go, they will kill their selvs in that small of a tank, not to mention that the will massively outgrow the tank (if they ever even get to grow)
I really dont know how it would be possible to keep a tank parameters in check with no live plants and more then like one fish in that small of a space
Also I forgot to mention it did start flowering. But they just fell off without ever getting tomatoes.