Your English is fine!
Your tank is a little small. Do you have the means to get a bigger (longer) tank? Since axolotls spend most of their time on the bottom of the tank, you should maximize floor-space, rather than depth.
How much water movement does your filter make? Axolotls don't like current, and can be stressed by a filter that moves the water too much.
Also, you should add some hiding spots for your axolotls, one or two for each axolotl. This is important, especially since your golden is quite a bit smaller than your dark axolotl.