what fish and how many could i have in a tank of about 50 uk gallons?
First off I'm not used to uk gallons, so if you know US gallons your going to have to see if I'm correct in saying this. From what I understand this is about 60 US gallons. (forgive me if this is wrong). What fish and how many?
You have to check water conditions and see how they are, and it depends on how you filter and how good you want conditions to be. I've had a 20 US gallon for about a year I kept about 4 fish in there. I'm just setting 50 US gallon tank, so I'm not sure how many fish will be in the tank. I'd just say add fish slowly and as your just setting it up, you may not be able to add fish very quickly.
It also depends on size of fish and what your looking for.
You might be able to have a few not so small fish, or a bunch of smaller fish.
what would i need for a sump such as what to put in it?
I'm not familar with them because I use a penguin bio wheel hang on filter.
i also heard before that you build the sump for your tank, is this true?
how big would the sump need to be for a tank of about 50 uk gallons?
I'm not sure, but if they are like filters I'm guessing they are rated. You should get one for at least the amount of gallons you have.