Hi i have a 3' x 1'  x 1' aquarium which is currently housing coldwater
goldfish however i am ready for the next step and having found new
homes for my goldfish i wish to refurbish my aquarium into a tropical
aquarium.

I am first and formost looking for a bigger/better filter for the tank
and am looking at a filter and heater combination that i have found for
around £29.99. Is this the way to go or would you buy a seperate
filter and heater? Are there any particular makes/models you would
recommend for a tank of this size?

Also are you aware of any good websites which catalog (with pictures)
the types of fish my new tropical aquarium will be able to house?

Thanks in advance!