Are All Heaters The Same Size?

[LastBoy5cout]

Thinking about minimising the stuff in my tank and was wondering if all heaters are the same size, my current one is huge and fairly old and difficult to hide.

I have a 200 litre tank.

Any ideas on a smaller heater?

 

[bronzecat]

Most of the 200w submersible heaters on the market appear to be around 11 - 13 inches. Only other option is if you are using a sump filter as I believe there are ways of heating the water in the sump? I personally dont know much about them.