Housing Mediterranean Moray (I counted four), shared with a very large Dusky Grouper. Really nicely designed with holes in the cobblestone walls for the eels. See more information in comment.
The triangular slab in the centre may look like tasteless decoration (I at first thought it was supposed to resemble a crocodile skull), but it is in fact far more interesting than that.
It is a lithic anchor dating back to Ancient Roman times, one of two or three such ancient artefacts that the aquarium, with permission from a nearby archeological organisation, has been allowed to use for tank decoration! I wonder how many other zoos or aquariums have two thousand year old artefacts in their possession.
While I'm at it, I may as well take this opportunity to remark on the colonnade appearance of every tank in the aquarium. The columns are actually semi-cylinders and do not touch the glass. I thought they added an extra layer of 19th Century charm to this building.
