my friend just got a tank for his birthday. he doesnt know if its a20 high or a 15. im helping him stock and cycle it. he wants swordtails for sure(i know they can fit in a 20,not sure about a 15),i reccomended a species of dwarf cichlid if its a 20(either a bolivian ram or a kribensis). i suggested a betta and a small school of tetras for the 15(assuming it cant hold swordtails). any other suggestions?