Why are the ends of the leaves on my Ficus Bonsai turning brown?
I have attached a photo below.

I am new to Bonsai and I want to make sure I am not killing my plant!!!!!!!

It is too dry in your place?
You water too little
It sits on a heater
It is infected with insects
It has received too much fertiliser
etc..

Could be anything. Please explain where it is,and how you care for it. A good picture of the whole tree might help.

Same happened to 2 of my ficus saplings a week ago, 4 leaves affected, i guess it is beacuse they lean over the heater a bit and I managed to get the substrate a little soggy, got to watch watering indoors more carefully.
Can´t wait for them to be moved outside and be happy again.