Politics aside permits will depend on city. Aquarium, inside home, probably doesn't need a permit as you noted. Attaching something to the house, HVAC, and things like that need permits. Different permits at that. One starts talking electrical, foundation, and what not - again a call to the city planning department saves one a huge headache if one sells the home. Again - you touched upon it. Doesn't matter if it is Ca or NY.
Before starting any large aquarium or buying a German Shepherd Dog, or similar high risk animal a call to ones insurance is wise. I would say common sense, but, most people it escapes their mind. Home owners insurance will vary. Call current, call others. You will be surprised.
Lastly I'll say this - this size project if it isn't something the hobbyist is comfortable with then I'd recommend talking to a professional installer and/or architect. Both even. They know the local codes or would know who to follow up with. Talking about the size and scope money isn't going to be an issue. If it is then this will be a good time to reduce scope and plan something smaller.
1,000 gallons is a lot of water so if you are not incorporating redundancy and fail safes then you already failed to reach low earth orbit.
Bean I know I replied to you but it is more just a ramble. I find large builds interesting because simple things or common sense things are often overlooked. Ca, solar generation window, battery bank, cost of water, supplies, etc.
Fun times.
