Zebra Danios need more space then 24" as they are very active fish. Cardinals are very hardy and yes they are pricey but it depends on the area you're in. Glo Lights, Black Neons, Rummynose, Red-Eye, Embers and Neons, it just depends on the source.When looking at fish check each tank for illness, like fungus, ich, sickly looking fish, and if its in one tank of one system... the whole system as it, meaning don't buy from that systems!