Whats the deal w these fish?

i had a female betta in a 10 gall tank by herself for a couple days yesterday I added 2 platys and 2 mollies. The female has been hiding on the side of the filter and has been swimming on side at times. The platys seem fine they stay together but are hiding behind some sunken ship in the tank. The other molly has been hiding in a plantbut isnt interested in food now but he ate in the morn. (i was just curious if hed eat). I replaced the molly that died with a new one so now theres 5 fish again the new fish seems completely fine hes swimming alot and picking at the rocks idk if the other ones are just scared. btw theres a heater and filter in the tank teh water is about 75 but i still have the heater on so it can go up to about 78