tank is in a mess at the mo, i pulled out some drift wood that i thought was causing problems & my new bit is still soaking in the bath, should be ready this weekend & then i'll replant. i have 1 blue ram 2 neons ( had 6!) some bn's & a gold spot. mine are quite shy & the ram is the boss in the tank. 2 are only about 5cms & the other is around 10cm, i lost my other big 1 a couple of weeks ago. so far ive found if they are well fed they dont seem to mess the tank up too much. mine get abit stroppy with each other but nothing to bad but i would try & get them all the same size, the slightly smaller one seems to bear the brunt of any rot between them. will take some pic's after the weekend. not sure on size, all the sites ive looked at have different ideas. the ones at wetpets in their display tanks are 15cm plus, worth a look.