What determines how ponds connect?

[Karasu]

So far I've noticed that most connect to each other, however there are exceptions:
Hammerheads connect to nothing
Pirrahnas and Angler Fish connect to each other but nothing else
Everything else connects

Am I missing something? Its so frustrating how I can have one massive pond and then have to ahve 2 other smaller ponds for things that don't connect. It really surprised me that Swordfish connect to the main fish but not sharks or Angler/Pirrahnas

[Unknown]

I'm not too familiar with sea creatures or have looked into each types history and evolutions. I would think that pirahnas would devour anglerfishes as they are cannibals. You can "connect" them with the water decoration for aesthetic purposes. You will still have to fish them in their own separate type cluster though with this method.

[Slab Grognar]

im also confused on how ponds connect

[YuffieG]

In reality the sharks, anglerfish and Pirahnas are dangerous to the other fish and would probably use them as a food source. However, Admiral Grumps have a point, I would think the pirahnas would probably devour the anglerfish so I have no idea why those two can connect to each other.

I've used a mixture of water lanterns and water squares to mix my fish together in certain parts of my farm so that they look like one huge water feature yet not having them swim in each others areas, whether they mix or not. For me it's just looks asthetically better but then I'm wierd like that!

[Obsi]

Seems the new sardines and bass don't connect to other fish tiles either. Or at least they didn't connect to the ponds of combined fish I tried to connect them to.

The floating bridge sections work well to disguise the fact some fish won't connect.

[Shady Dog]

I really don't think there is a connection to real life logic in what connects to what. Seems like, if anything, that saltwater fish should attach to saltwater fish and the same with fresh water fish. Of course salmon would have to connect to both.