Snails & Sexing my goldfish

Question
Thank you changed my water and got myself some bumble bee horn snails which are doing fine.

Another question i have a 50 litre tank with 1 shabunkin, 1 fan tail and now 2 snails how many fish would you recommend for a 50 litre tank?

Thanks
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The text above is a follow-up to ...

-----Question-----
I am new to fish and purchased my first tank & Goldfish (Shubankin & Fantail)about 9 weeks ago how do i go about sexing these fish? Also i have add one snail (not sure the breed)to cut down on the algae on the glass, problem is he lies on his shell on the gravel and doesnt go near the glass, is this a sign hes dying or ill?
-----Answer-----
To sex your goldfish you will want to check out the link I have included as sexing goldfish is quite difficult.
http://petcaretips.net/sexing-goldfish.html
Have your water tested, snails are extremely sensitive to water conditions which can cause problems as healthy snails are usually quite active in a tank. Once you have the water tested it will be easier to narrow down the problem or cause of this behavior. Best of luck and happy fish keeping.

Answer
One inch of adult fish per gallon is typically the rule of thumb. I will be honest and tell you I don't always follow that rule, the secret to having more than the rule of thumb is simply water quality and compatibility. So, what you have to do what you feel you are ready for. If you are relatively new I would follow the rule until you are more comfortable, exspecially seeing goldfish tend to produce more ammonia in the water than other tank occupants. Best of luck and happy fish keeping.