What to add next?
 

I finally got some fish, I added two Redtail Dalmation Platys four days ago and today I added two Redtailed Black variatus (I think they're the same as Tuxedo platys) I was wondering if anybody had a good idea of what to add with them?

What is your tank size, has it been cycled, is it in the process of cycling, what do you 'want' in it, tank stats. Just a few main pieces of information needed please. Than I will try to give you all the help you need.

It's a 20 gallon hex, it's been cycled for 2 weeks empty and then two more weeks with a pair of bettas (male and female) In it I have the 2 platys and 3 bettas (2 females and a male) So far everyone is getting along great so I'd like to keep the male betta in there so NO fin nippers. I'd just like more colorful/unique community fish...perhaps a school. I saw some dwarf puffers at Petsmart does anybody know if they would work or if they are too aggresive. Also, how many fish should I put in, is 5 enough or can I put more?

Forget the dwarf puffers. They can nip and are best kept in a species tank. Go with lemon tetras. Avoid neons as they won't thrive well in the early stages of the tank.
Beacon tetras(Hemigrammus ocellifer) are another choice.

Male guppies might be an idea: some of their colours are absolutely stunning. They won't go after your male betta, but watch the male betta for going after anything with long, colourful fins. Keep in mind that some of the long finned fish (such as guppies) don't like much current in the water. As for how many to add, a general rule of thumb is one inch of fish per gallon of water in the aquarium; but when you calculate it, use the size that the fish will be when it is mature, remembering that a fish that is one-inch in size now should be given adequate space to reach it's maturity size. :)

That is no longer applicable. It is now considered a myth.
The needs of the fish or animals should be taken into consideration. These needs may include:
Proper room for the Activity Level and Swimming Space-Swimming levels/niches, the animal’s usual style or level of activity such as ‘laps’ around the aquarium, schooling, and skittish behavior common in schooling fish.
*With schooling fish, the length of the tank is very important as in the wild, they shoal in long distances(pretty much applicable to fish with slim body shape and fish from river rapids).
Territorial requirements–the floor space or empty room between individuals.
Vertical space-most taller-bodied fish require room above and below their fins.(most applicable to discus and angelfish)
Compatibility issues-many aquarium inhabitants will not be able to live together properly to the end of their natural life spans.

As for the different levels occupied by fish, this consists of:
Surface level-fish with upturned mouths(usually hatchetfish and butterfly fish), pencilfish
Mid level-fish with mouths forward(applicable to angelfish and discus)
Bottom level-generally catfish and loaches although most cichlids tend to occupy the bottom like the Tanganyikan shell dwellers

For the stocking levels, for example in a 30 gallons tank, there are 10 kuhli loaches, 15 harlequin rasboras and 15 hatchetfish. We do not consider this as overstocked as different fish occupy different levels of the tank.

So then how many middle level fish could I have in my tank? I plan on adding two cat fish eventually and a pair of otocinclus...

I'd forget the platies and plan for about 15 harlequin rasboras but you need to finished cycling first.
Add otos only in the later date or make them the last to be added. They are sensitive to the changes in water chemistry.

I think I'm done cycling...I have 0 nitrates 0 nitrites and about 5 nitrates. I guess I'm not sure exactly but I've added fish and they're all doing super great. I have 3 bettas 2 redtail dalmation platys 2 variatus and 4 glass fish as of yesterday (I was going to add rasboras but my bf had his heart set on the glass fish) so I'm pretty sure I'm done until I start growing algea and then I'll get the otos and a bottom feeder or two. I really don't want to over do it, but I have a 30 gallon filter on the 20 gallon tank. I'm actually pretty proud, they're all healthy and active and just look awesome!!!

Congrats on the tank. Some advice on the fish is just take is slow, and be patient!