i have a 35 gal tank. its has 6 cardinal tetras, 6 penguin tetras, 4 platys, 2 ram cichlids and 4 amono shrimp. al fish are happy. ph is 6.5. planted with plenty of swimming space. i would like to know if i can stock any more tetras. i have heard that if you stock multiple breeds they will fight. if its ok can you please give suggestions or can you please list any other small peaceful fish that will fit into my tank