What size is your tank?
First pick your Favorite fish (does it fit the tank when grown) everybody has one mine is Gold Gourami they have a personality and greet me at the window if I sit near.If I touch the glass they lie on their side as if ready to be stroked.
Build from their around your pride and joy
Here is a list found on another forum I posted the thread at the end
Group 1
Neon Tetras, Glowlight Tetras, Harlequin Rasboras, White Clouds, Fancy Guppies, Corydoras Catfish, Glass Fish, Honey Gouramis, and Ghost Shrimp. These fish are compatible and a few of them will do well in a 15-gallon aquarium with warm water. These fish are not compatible with most other species of fish. Click here for more about warm water aquariums.
Group 2
Danios, Swordtails, Mollies, and Platies, plus Bigger Tetras such as Black Skirt Tetras, Painted Tetras, Serpae Tetras, Red Eye Tetras, Black Neon Tetras, and Silver Tip Tetras. A few of these fish will do well in a 15-gallon aquarium with warm water. Each fish species in this group lives best in a group with several member of that species. Click here for more about warm water aquariums.
Group 3
Barbs, Gouramis, Sharks, Eels, and Loaches. Tiger Barbs and Tinfoil Barbs, plus Blue, Gold, and Opaline Gouramis, plus Bala Sharks, Red Tail Sharks, Rainbow Sharks, and White Tip Sharks. These fish are mildly aggressive and compatible with each other. They will grow fast and need at least a 29-gallon aquarium with warm water. Eventually they will need a much bigger aquarium. Click here for more about warm water aquariums.
Group 4
New World Cichlids. Firemouth, Convict, Pink Convict, Texas Cichlid, Jack Dempsey and other New World Cichlids are very aggressive fish. But many aquarists enjoy watching them dig, defend their territories, and care for baby fish. Large Plecostomus Catfish, Synodontis Catfish, and White Tip Sharks are usually compatible with New World Cichlids. Within a year or so a group of these fish will need an aquarium with at least 50-gallons of warm water. Eventually these fish will need an even bigger aquarium.