Hello. Im writing this as a kind of online track of every mistake I made with my aquariums.
Some of its funny. Some of it is sad. Alot of it is just stupid. Yes, I said it so you dont have to.

First I bought a small 2 gallon from petsmart. Along with filter and gravel and food it cost me $50. it was a name brand one. Here's something that I didnt know. Bet you already knew though. Cause you are experienced and probably dont have OCD. In the stores a 2.5 gallon costs MORE than a 10 gallon. Makes no sense, but the stores all have them that way.

Anyway. Once I got the tank setup I bought the blue bully. A rather ornery looking Betta. He had plenty of personality and used to swim to the front of the tank when I got close. After a month or so I decided. I need more fish. So I looked up a few stores and went fish viewing. I asked every question I could think of. Eventually I ended up in a local store that was really helpful. OR so I thought. When I asked the the nice sales girl is there anything a betta wont attack she pointed out some Rainbows. "they will get bigger so he will leave them alone. I have two in a tank with my betta." I took several days to think about this and bought two of them somewhere.

When I got home I let them acclimatize and made dinner. This was my first mistake.
I wasnt watching. If I had, I would have know blue was hitting that bag like a jock pounding a fat kid. But I didnt so I released them into the tank. Everything seemed fine. a few hours later I went to bed. The next morning I got up and did a feeding. Everything seemed the same. Rainbows on the left side, Betta on the right side. Little did I know blue was waiting. Kinda the way your older sibling waits for mom and dad to leave so he can kick the crap outta you.

When I got home one of the rainbows was missing a tail. I got blue out and put him in a bucket. Then I got a 10 gallon from petsmart nearby. I set it up and put the rainbows in it and blue in his tank. Things were peaceful.

Three days latter I got a blue gourami from my boss. It had been bulling the other two and it needed to be moved. So brought him home and 'plop' into the rainbow 10 he went. To this day I have no idea what happened. After an hour, I heard a loud splash and rushed to the tank. Both the rainbows were floating and the gourami was staring at me. It were possible, I bet he would have given me the finger. So he had to go.

The next day, blue developed a black dot on his side. Within 10 hours it took over his whole left side. At about 1 am he simply stopped swimming and hit the bottom.
Was it an infection? a bite, as someone suggested? No clue. I just know in 10 hours I had a dead betta.

I took everything in his tank and either boiled it or tossed it. Same for the 10 gallon.
But what do I do now. I have two empty tanks with gear and no fish. What would you do? Damn right. Go buy some fish.
I bought another Betta. He showed every sign of having issues.
He wouldnt swim. Just float. He wouldnt eat. I took him back to the store and showed the "fish expert". She smirked at me and said, "sir you have to take him out of the cup and put him in a tank". She insisted he was fine. then her helper came over and insisted he was fine. So I took the fish, flipped them a "goodbye" and left. I went to another store and bought another betta in the same color.
By now I had a second one gallon tanks sitting around. So I filled it and put one betta in it and one in the 2.5.
Three days later one betta died just like I knew he would. Yes, the sick one.
Now I still had an empty 10 gallon and a burning need to fill it.
so I read and read and read. I know what color ranges I wanted, I just need to find them in peaceful fish. Flame gouramis. Yep. They are docile and can be community fish. I dont know who writes these characteristics, but I can tell ya the fish dont read 'em. I bought to flame gouramis and put them in the 10 gallon. You would think 5 gallons each in a semi planted tank would be fine. no. The next day they were going at it like immortals.
There could only be one
Deciding hastily I ran to the store and picked up another one gallon. I set them up and dumped a gourami in each. Things were fine for a month. One night I was going out to meet friends. I decided to do a water change before I left. Conner (flame gourami) was stone dead by the time I got home. I did a dumb thing. I decided to do a water change on the same night I was going out. What do we always do when we rush? Forget something. I forgot to treat the water before I changed the second flame.
This left me with a betta who was happy and growing. A flame gourami (Kurgan).
but I also had a 10 gallon that was empty and an appointment to pick up a 30 gallon.

The original idea was that the gouramis would be in the thirty and the betta would get the 10. I didnt want Kurgan in the 30 though. He had proved to be violent and I didnt trust him. So I put Kurgan in the 10 and planned my 30.

Now a number of people would have said, screw this, Im done. I one the otherhand was sure I could get this right. I just needed to research more. So I did. More schlepping to stores looking like a nut, asking questions and not buying anything.
when I thought I was ready I went and picked up some Honey sunset gourami. Small, non violent, attractive, cheap. So I brought them home and set them in the 30 gallon.
It took all of an hour. One of them decided the other two look like someone that owes him money and he went to town on them. Something had to be done. Out come the one gallons. Problem solved right? Wrong. I have a 30 gallon that empty and a bunch of fish that cant get along. Not to mention I had tanks popping up in every corner.

So I built a plan of attack. I got a decorative tank for the betta. I moved two sunsets to the 2.5 and left one in a one gallon on my desk. Kurgan still had his 10.
A month later Kurgan's mouth locked open. I tried to save him but in the end, he was having trouble eating, so I froze him.

To feel better I went and bought 4 angelfish. Things went pear shaped the day after I placed them in the 30. The next morning one was dead. I blamed myself and started checking the tank out and did a 30% water change. No problems found. The next day another one was dead when I got home. WTF I screamed. I did another 30% change. Everything seemed ok for the week. It was a saturday. I had just made coffee and I was watching the last two angels. Thats when I saw it. One angel slowly drifted by the other, then suddenly turned and slammed himself in the other. He was a ninja. For some reason he just didnt want to share that tank. So I took him back and got three more. On a bit of bad advice I moved them to my 10 gallon.
So now I had 4 angels in a 10 gallon. Hey. I said it was bad advice, didnt I?
One was dead within the week. Two days later my gouramis in the 2.5 died. Three days later, I came home to all the angels dead. Ripped fins, torn tails. I think the 10 was too small.

Now i was going to give up. $300 in fish and equipment and all I had to show were carcasses. I made a stop at a local store to tell the owner thanks for his help, but I was done. He was sympathetic and offered help and advice.
Armed with this new knowledge I bought three more angels and ran home.
Everything was fine for this month and then two of them stopped eating. they went into hiding under the plants and would not come out.
thinking there was a bully in the tank I took out the one with a torn tail. The other two perked up for two days. So I added a few more plants to the tank. That was a huge mistake, Touching their water seemed to make all the difference.
They went into hiding for the next two weeks. I didnt see them all until I got up for work and found their bodies floating.
I got the water tested and it shows Nitrites. Course I did a water change a week before. They didnt care. They died anyway making me look like a fish serial killer.

What? The 10 gallon. Looks great. Somehow I always forget that
It is loaded and stocked with cory cats, long fin tetras and a couple of german rams. Been that way for a month I think. Maybe more. I tend to forget about it cause I never have to do much with it.