from cold water to tropical

[IamTheWhoreofBabylon]

I have a 200L tank with rosy barb, minnows and shrimp
My local shop said they would all be happy if I made my tank tropical
I have been thinking about it, it came with a heater
Is looking after a tropical tank just the same, same amount of water changes etc?
I am thinking neons would look nice with the fish I already have

You can, but you need to acclimatise them slowly. Dint ramp up the temperature too fast. I'd aim to raise the temperature over a week or two and try to find the overlap of acceptable temperatures and keep it in the sweet spot.