Here I recommend the easy-keeping fish. 
1. Crown Tail Male Betta Fish
These fish are popular due to maintenance requirements and their bright jewel-tone colors. Bettas can live in any aquatic environment from a small, lowly filtered bowl to a large filtered aquarium.
2. Tetras
These fish are popular due to their hardiness, non-aggressive temperament, and small size. It is quite easy to keep multiple Tetras in a tank together and they do not require large tanks. Most species of Tetra can be kept together quite easily.
3. Guppies
These fish are popular due to their small size and colorful fan tails. Guppies are very hardy fish and since they are livebearers, it can be fun to watch the baby fish appear and grow in the tank.
4. Platies
Platies are very adaptable to a wide range of tank conditions and are also livebearers… so you may end up with more than two! They are bright in color and make wonderful pets.
5. Molly fish
Mollies are hardy and fun, live-bearing fish. They are gentle and undemanding and because of this, maybe bullied by other fish in a community tank so be sure to keep an eye out for them.
More recommendations are being welcomed.