Great rock work and nice looking fish. There is one thing I would change though IMO. I think that the gravel layer is too thick, it may look thick because the fish have piled it up in the front of the tank but I cant tell from the pictures if there is a big hole behind the forward pile.
I am aware that you use an under gravel filter in the tank and that a certain amount of gravel is required but I think you might have a bit much. In the majority of your pictures the gravel layer looks to be about 4-5 inches in the front, IMO this will lead to an increase in extra unwanted debris in the tank as substrate cleaning will be more difficult, could possible lead to an excess build up of anaerobic bacteria and it reduces swimming space. Even with an under-gravel filter you should only be using 1-2 inches of substrate and I personally believe that the less substrate in a tank the better!
Regards