That and the standard of the art. I really don't like the use of human artefacts or art in enclosures, whether it's something like this or tiger/monkey temples, Aztec ruins, etc etc.
That's not to say that this exhibit is all bad, the tank is a good size, but it is a bit bare. Maybe some empty tequila bottles and other relevant rubbish near the clay pot could be used to at least illustrate the encroachment of Mexico City on wild axolotls.
axolotls don't appreciate cluttered tanks because they are quite clumsy. So long as they have some cover in the form of rocks (or pots) to lie under or beside then they're happy. The main thing is that they like low light levels (I just put the light over the tank to take the photo; usually it's unlit).
Honestly though, are you comparing marmosets living inside a glorified doll's house deliberately built as a joke on the animals to domesticated pet-store axolotls living in a tank with a colourful painted backdrop? I don't really see the comparison (I mean, I do to an extent, but I'll continue to rally against exhibits like Wellington's marmoset house).
