soo here are my questions
1) if I were to use a 20 gal, how many lionhead goldfish could I keep in there?
2) how would you go about setup? I read that gravel is a no no, and the less plants/decor the better
3) I plan on having a filter, possibly two, what are the best you suggest?
4) Any advice? things you have learned about caring for them?
5) I'm thinking two in the 20 gal would be great, since they grow to about 6 inches if my research is correct.
6) Is it true they need 8 hours of lighting?
Thank you SO SO SO much for answering my questions you are awesome!
Personally I wouldn't put two fancy goldfish into a 20 gallon tank. While they don't grow as long as the common types, they are much bulkier and like all goldfish, produce a lot of waste.
I would go for a 30-50 gallon tank. That gives 15-25 gallons per fish, which I think is more suitable for such a large and dirty species.
I use a large grain gravel in my goldfish tank. Mine spend a lot of time sifting through it for leftover food. Barebottom is usually only for convenience and easy waste removal. As long as you choose an appropriately sized substrate, it should be fine.
External filters are great in terms of the large amounts of media that can hold. However, they are pricey, and a couple of large internal power filters (I use Fluval 3 and 4 Plus in my goldfish tank) should do a decent enough job. You might need to install a spraybar, or baffle the flow if your goldfish are having difficulty swimming. I own shubunkins, and they have no issues dealing with the current.
My goldfish only get natural light. I don't know where you heard they need 8 hours, I assume that would only be the case if you had live plants in your tank. If you don't, 8 hours of light might cause problems with algae.
Goldfish are pretty easy once you have the basics down. I do 25% water changes twice a week on my tank and feed them NLS pellets and flakes, as well as Hikari frozen bloodworms and brine shrimp.
They do prefer harder water, so I use crushed coral in my filter to bump up the KH and pH (our water is incredibly soft out of the tap here). While mine don't eat plants or vegetables, I know some do enjoy a meal of lettuce or blanched cucumber, peas etc.