want to set up a small 5 gallon aquarium for my apartment, looking at the 5 gallon eclipse lookalikes at walmart, wondering if i could put three platy and maybe two sword tail in it (does sex of fish matter? if so how can you tell the difference), i guess the aquarium comes as a kit with most of the stuff, but do i need anything elseother than plants and gravel? any advice would be appreciated! thanks!