It is better to raise some fish. Can I keep 13 fish at home? Can my fish tank put things now? My door faces north.

If you consider geomantic omen, you can't tell the door faces north, the cylinder faces east and the cylinder faces west. But on the whole, this arrangement is ok. Many people sit east facing west, and of course many people sit west facing east.

Why choose 13 for the number of goldfish? 13 is not a traditional lucky number in China, but it would be better if it is 16 or 9 or something like that.

Judging from the difficulty of raising fish, the less fish, the better. I don't know how big your tank is. My own experience is that it is 10 liter of water, 1 goldfish, and it is based on simple filtration.