Hi there. I've added a link to some information on axolotl housing:
Axolotls - Housing in Captivity
It says that a 45cm long, 10 gallon tank is the minimum for 1 axolotl. Some people say that it should be a minimum of 40 gallons, but I don't know if that is a mix up from conversion factors because we go with litres in the UK, and we use a general rule of 4o litres minimum tank size per axolotl. Basically, the more room the better for the axolotl to explore.
The wood in your tank does take up quite a lot of the floor space. They will climb over things, but they do like to go for a walk. Perhaps you could consider raising one end of the log, so your axolotl could use it for a hide and/or walk underneath it.
Is the white oblong a feeding dish? If so you could also try using a smaller one. In the past I've used the upturned lid from a jar for feeding bloodworms to my juveniles when they were younger, but that was on a slate so they had plenty of space away from the sand when they were eating (sand isn't good for small juveniles).
Also make sure that your pebbles are too big to be swallowed.
I hope that this was of some help, and please keep us updated on your progress, and post lots of pictures when you get your axolotl.
