How to tell the deference between a male and female sunfish,bluegills,red ears, green sunfish etc?

i caught 3 sunfish one smaller than an icn one an 1 on the last one 2 1/2 inches they in a 5 gallon tank with mosquito fish i willl put them in a bigger tank then they are big enough not to be eating by large fish in my tank they look like bluegills but i have no idea what they are they have a black dot near there eye like an ear they have a lil red on there eye and i want to know how to tell i it is a boy or girl and if you think u know what kind of fish this is post a picture plz and thx you