Andros is Layla's home planet. It is a planet that is predominantly covered in water with a few jungled islands. There are also the ruins of buildings above and below the water which were never explained. The King and Queen of Andros are Teredor and Niobe, Layla's parents.
A portal between Tides and the Omega Dimension was built long ago and sealed. Valtor, with the help of the Trix, opened it to escape. Leaving the portal open caused havoc on Tides, and would have led to the planet's destruction if Tecna had not sacrificed herself to close it.
There is also a magical link between Tides and the oceans of other planets in the Magical Dimension. In Season 3 Layla swam into the ocean on Magix to emerge on Tides. According to Layla and Tressa, the depth of the Ocean of Tides does not reach to and end and does not have a bottom.
A large and dangerous legendary creature called the Kraken lives deep in the oceans of Tides.
There are two dominant races: mermaids and humans. Both societies are run by a monarchy with the mermaids clearly matriarchal. The mermaids became monsters when Valtor put a dark spell on them and gained control over them.
The human/fairy/wizard society exists on the surface of the planet. Layla's family is the predominant royalty, while Nabu is a member of another such family.
A merman has never been seen in the series but it does not mean that they do not exist. The merfolk have wings and can fly, as well as live out of the water.
The mermaids have the important task of guarding the portal to the Omega Dimension.