How long do I need to run the tank before I put fish in there?
Two weeks to a month is a safe bet, but some will cycle their tanks for much longer. It really just depends on how long it takes to get your parameters under control and to make sure everything is running smoothly.
What do the water parameters need to be at?
Nitrite and ammonia should both be at 0.00ppm by the time you're ready to put your fish in, but it'll fluctuate from time to time and will take a good few water changes once you've added fish before you can get the parameters to a good level.
It really depends on which fish you get. If you're getting tropical fish like tetras, corydoras, guppies, e.c.t, the tank should be at a comfortable 25-26c. You can find heaters pretty easily that are pre-set to the right temperature and are usually pretty reliable. If you have cold water fish like goldfish you don't really need a heater.
Any advice on what kind of fish could be added. I’d really like a bright interesting tank. I would love a betta in there for definite as they are stunning. So anything that would get along with a male betta. If that leaves me limited then what else could I add?
The choice is yours. However, if you're looking to get a betta be aware that you can only have one male in a tank because, if you have multiple, they will fight and will often do so until the loser is dead. Not to mention, bettas can be aggressive towards other fish so it's always good to do thorough research on the fish you're looking to get to see if they're suitable to be with a betta.
Since you're looking for a bright and interesting tank, I would personally recommend dwarf shirmp/cherry shrimp as they can come in a wide variety of colours such as red, yellow and blue. Neon tetras are a staple of tropical tanks, but
@CassCats has noted in their Unpopular Opinions thread that neon tetras can be "mean little turds" and can be aggressive towards one another.
had 10 and they constantly fought with one another, nipped each others fins, and even bit one of the face off one of them. Nothing but conflicts with them and they've started going after my other fish in the tank too, so I ended up rehoming all 10 lol
Rummy nose tetras are also lovely, and they bring a beautiful burst of red to your tank. Tetras are schooling fish, which means they need to be in groups with one another. The recommended minimum amount of tetras is around 8, but you can go higher. You should generally stick to around two (three at most) types of tetra if you intend on getting multiple kinds of tetras.
Guppies and endlers can come in beautiful arrays of colour, but live in different water conditions to tetras typically so it's up to you whether you intend on taking this gamble or not. Personally I keep tetras and guppies together and have had no issues. Both the guppies and tetras are quite happy. However, be careful with guppies:
A tank of males can lead to aggression, but a tank of males AND females can lead to breeding. And then lots and lots of fry. I mean
lots.
Hope this helps, keep us updated. Would love to see your new tank!