Ok i've been thinking about changing my tank to tropical and rehoming my shubunkins, and was wondering if Just changing the filter media in my marina s15 filter to the tropical cartridge things with my extra filter wools behind them and just putting a heater in I got with the tank, so would I just be able to leave the same water in and increase the temprature to between 23 & 26 degrees celcius our would I have to completley restart the tank by haveing to renew all the gravel to get rid of goldfish poo our will that not matter as bacteria eats it? thanks.

Hi Cambonjr,

I would completely agree with Nossie, please research as much as you can about any fish you are interested in keeping.
I find this website quite handy as it can give you a rough guide on stocking and fish suitable for your tank; (Link is not visible to guests. Please register to view.)

But again, any fish the website comes up with that interests you, I would still suggest you research them, as some tropicals prefer sand, others gravel, they might have different diets, different compatibleness and all of them have different ph/temperature ranges 

Good luck!

suggested easy(ish) starter set-up
6-8 Neon Tetra

6 Assorted Danio

3 Cherry Barb

3 White Cloud Minnow

4 Platy or 2 Swordtail