Betta Fish: is my tank too big?

Hi, first time post and purchased a betta some weeks ago.

TLDR

I'll put the short version first. I purchased a beta and put it in a 5 or 10 gallon tank. he let me pet him and I went out and purchased a 45 gallon tank. I treated the water with softener for tap water and added some treatment for bacteria. I stirred the water and let the filter run for about 2 hours. put new plants and a little hideout in then threw Snack (my fish) inside. He was flaring and getting aggressive with his reflection – I'm going to fix it with other lighting and paper when I get home. The bigger concern is… the water was still a little cloudy. it seemed slightly cloudy and I'm afraid he will get sick and Snack did not seem as happy in the tank.

The story.

I wanted a fish so my kids could have a little bit more responsibility for a live creature – of course I'd make sure it was being fed and the tank cleaned, but so they can feed it and "take care" of something simple other than dolls.

The setup was a 5 gallon or 10 gallon tank, 2 plants, a small light on top, filter, and blue grey rocks. I used filtered water – the Brita filter that attaches to the sink faucet. I felt throwing a fish into a tiny bowl was kind of sad and that's the only reason I got a tank the size that I did.

I never paid much attention to the fish other than making sure the tank wasn't dirty and making sure it was getting fed every day. I honestly thought you can just put a fish in a bowl of water and it would be fine as long as you keep it clean. I've even seen fish swim around in heavy cloudy and dirty water before.

Well, one morning when I was getting for work I walked past the fish tank and noticed Snack swam to the front of the tank , leaving the plants he usually likes to…relax? around. I've seen him swim in the front of the tank before but didn't think anything of it. when I noticed him leaving his spot, I jokingly thought to myself "my wife is going to be so jealous that the fish likes me". I thought it would be funny to tease her about it. That did plant the seed though and I did start paying more attention when I would get ready for work in the morning. Every morning and whenever I got home from work and walked past the tank I would see him leave his spot and come to the front.

After about a week of paying attention I decided to look it up. still in denial that a fish would … want? to see the person who feeds it. At the very least, come out for food because it recognizes the person who feeds it.

When I looked up more info. I was surprised. "fish puppy" "recognizes its owner" "intelligent" "can be taught tricks" etc.

I started to feed it from my finger – you know, sticking the food on your finger and dipping it in. Then I started just putting my finger in a few times a day so he can get used to me a bit more. Snack never really zipped away when I would stick my finger in but he never got too close at first either. Then he started brushing up and then eventually would rest against my finger.

that's when I went out to buy the little guy a new tank .. I impulse bought a 45 gallon tank because I wanted him to have a bunch of room to swim and be happy. I got the water treatment chemicals, bigger filter, plants. hiding dome, drift wood, thermometer, and a water heater because he was resting on the pump – I learned his water was too cold.

I got the new tank today and set it up. I did some water treatment, and set up all the goods. I used unfiltered tap water…because 45 gallons… let the water circulate for about 2 hours and tossed him in. He didn't seem too happy. the water was slightly cloudy – I think because it was unfiltered. his other tank was super clear and looked very nice.

Also, when I would feed him – I'd sit there and watch him eat. So that's probably why he recognizes me.

is the tank too big?

is he going to die because I messed up the water?

any advice is appreciated.

note:

English IS my first language. I suck at it. I'm on my phone and my fingers hurt too much to edit.