Fish has an incredibly stable mana base and does not pack cards like Mana Drain or Intuition/AK - staples of a Tog deck - that make the Psychatog so powerful.
Fish doesn't have an incredibly stable manabase. In fact, it is one of the deck's largest flaws.
The main problem with adding Tog to Fish is that the deck doesn't gain anything off the inclusion. Straining Fish's mana further to support a creature that attacks for 1 and costs 3 isn't going to cut it.
Like the others have said, Tog has no place in Fish, you're better off playing wither Gay/r or GAT/Hulk.