- Decide what size aquarium/fish tank you want
- Get a filter, aeration, and a heater for tropical fish
- Cycle your aquarium
- Research the fish before you buy it
Having been completely new to the aquariumist hobby we were looking for information anywhere we could find it. Interestingly some details get left out very often as if they're common knowledge everyone knows anyway. I decided to share what we've learned including all the little details to hopefully make it easier you.
1 Decide what size aquarium/fish tank you want
The main thing here is; the bigger the aquarium the more care needed and the more money will be spent. If you have the space, money, care, need, and patience for a big one, then by all means go get one. However if you're reading this article you're probably completely new to the hobby, and my advice to you would be to get a small tank to start with. The 10 gallon/38 Litres size tanks are recommended for beginners here in the U.S.
2 Get a filter, aeration, and a heater for tropical fish
Something I wish somebody would've told us early on is that the filter does not come with the beneficial bacteria everyone talks about. You put it in by cycling the aquarium which I'll talk about in my next point. You'll also want aeration for your tank, aka some way of getting the air bubbles in your tank. Contrary to what I believed those are mainly not for the fish but for the beneficial bacteria in your filter. And yeah, you may want a heater for your aquarium depending on what fish you buy, because even if cold water might increase their lifespan by slowing down their metabolism I don't think it'll be very interesting to watch fish who are barely moving.
3 Cycle your aquarium
Now that I really wish somebody would have told us before we did anything. Fish produce Ammonia which is toxic for them, a properly working filter has two types of bacteria. One that converts Ammonia to Nitrite, which is even more toxic for the fish, and the second type converts the Nitrite to Nitrate which, in the quantities it'll be in your aquarium if you replace the water when needed, is not toxic for the fish. These beneficial bacteria appear over time with a filter in the aquarium. So if you can't wait to get started you can put fish in your tank, but you'll have to closely monitor your Ammonia and Nitrite levels for a while and change the water more often at first which, the maximum amount of water to change is half your aquarium capacity but the amount you should really change is closer to a 1/3rd of the aquarium or better a 1/4th because the less water you change at a time the less you throw off the bacterial balance.
4 Research the fish before you buy it
If you want several different life forms to live peacefully in your aquarium, you'll want to make sure they can actually live peacefully together. One advice I can give you here is every fish has its own character but generally, if you want to buy a Betta that's going to live with other fish in an aquarium choose a female. And better yet, choose one that's already living in an aquarium with other fish at the pet store as its already going to be accustomed to having roommates. If you're not going to have any other fish in your aquarium besides a Betta, then you can go for a male which are generally much better looking.
Good luck!