im just about finished setting up a new 20g long tank with a penguin 150 and i was thinking of getting 5 zebra danios and 3 ghost shrimp to help cycle it. is this good enough? should i start with more than 5 danios?

also, what other fish would be good to add after the tank is cycled? i was thinking some corys(3) would be good. maybe some neons(8) too.

With a 20 gallon tank, you have a large selection of small fish to get. From the looks of it, your getting community fish. For Tetras, Danios, Rasboras, ect. The golden rule for most of them is to get 5+ of the species of fish you want.

5 Danios, 8 Neons, and 3 Corys would fit perfectly in a 20 gallon.
I don't know much about Ghost Shrimp however.

I would wait on the neons till the tank is more established, they are pretty sensitive. Also when you do get the neons try to find some that are a little older than the small ones that you see all the time as they are hardier than the younger ones.

6 tetras
6 danios
&
6 cories

Would be pretty cool in a 20g :rockon: :nod:

i've found danios to be the absolute best starter fish

I would get glow fish, just cuz they are cool. Impress you frinds by swiching the tank light from your normal one to a blacklight. That way you can see the best of both worlds and diffrent fish in one tank. They get along with other community fish as well.

I know they are geneticly modified but its in a cool way.

If you haven't gotten any fish yet, why don't you do a fishless cycle? It's quicker and easier and no fish are harmed or killed while you do it. Do a google on 'fishless cycle', I've lost my link to a great site on it and will go look for it.