Best Pet Fishes

What is the best pet for small fish can be kept in a small tank? Thanks !!!!!?
Thanks for your answers !!!!!
How small is this small tank? From what little information I have given, I'd say a beta would be the best bet. Just remember not take too well with other fish (including itself), if you decide to get later. Goldfish are good, but can grow quite large if they live long enough. Mine is about 6 inches long and seemed full of 10 gallons. But it seems at home in their new 50 gallon aquarium
Goldfish also produce too much ammonia in water that can kill quickly without frequent changes of water and a good filter. You may want to also examine more options unique company. We African clawed frogs with goldfish. They are fairly low maintenance (actually a little easier to care for than goldfish) and look so cool! When people come, I wonder if the frogs are real
African clawed frogs do best in large tanks once they have grown, but smaller aquatic frogs can do well in a small tank. Good luck to choose the right
Pet Fish Care : Beginner Saltwater Aquarium Setup