New to looking after Axies

Hello,

I recently got 2 Axolotls for my birthday.
It was a surprise, I was cycling my tank ready for fish!

Anyway, a friend of mine has an axie and thinks my tank is the wrong type to keep them both in.
I have a 35 ltr tank, its one of the round ones and is taller than it is wide (13 inches diameter and 18 inches tall).
He thinks the water is too deep (16 inches deep / 3 inches from the lid) as well as the tank being not wide enough.
I have a large silk plant in there which covers the back of the tank from top to bottom.
I also have an ornamental platform which looks like a base of a tree and roots so they can nip in and out ad well as a flat top some 5 inches from the surface.

My Golden albino one likes swimming to the front of the tank especially if i'm stood there with a pot of worms!
I also have a black one who prefers to lurk at the back of the tank behind the leaves.
I've seen them zip about a couple of times, usually when i accidently knock the ornamental vine thingy, they will generally do a few laps and then settle down again.

The seem happy enough, should i be getting a more suitable tank?

A bigger tank would be better - Axolotls can grow quite big (over 30 cm) and prefer a lot of floor space. It is also easier to keep a bigger tank stable concerning your water parameters.
I do not think that the tank is too deep - after all Axolotls are aquatic animals and rather seldom need to get some air from the surface.

pictures

pictures would help use juge the problem but danial is right they like floor space when my axolotl was young it swam about alot but now hes older he walks around and my tank is 3ft by 1ft and he loves the floor space so in the future i would get a bigger tank and use your tank for something else like newts or fish newts are better though but we need pictures to make sure of this .