i just bought 4 lil black mollies yesterday and i can't wait to see some babies. i'm so new at this though. and i dont have those fancy tanks.mine's just a plastic aquarium,is this enough? i have several questions and would appreciate any help: 1) how do i tell if a female is pregnant? i have 3 females. 2) i dont know if i bought the wrong type of food. i have not seen them eating so far,is this normal? its the little round red and green stuff. should i get flakes? 3) flounder sometimes goes ballistic and starts swimming in a squirmy way. am i doing something wrong or is it some weird mating swim-style? 4) do i have to get those oxygen crystals? 5) do i really need aquarium salt or is it optional? they dont use aquarium salt at the pet shop i bought them from.