It depends on the size of fish you want to house in a 55 gallon tank. Fish come in various sizes,
You can house upto 25 to 30 pairs of just guppies, mollies, tertras, Danios, Angel fish, Dwarf
Gourami's Cichlids like Ram's, platties, Rasboras, You can mix most of these fish and have a
colorful looking aquarium. With good lighting and some tropical freshwater plants, you got yourself
one of the best tropical aquarium. For people to admire your aquarium the trick lies with keeping the
water crystal clear. Live plants do a lot of waste removal. They are real natural filters.
If you say you want to house some larger species in your tank,
Then probably you can at most fit 5 fish and should be all of the same temperament.
1. Fresh water Sharks,
2, Tiger Barbs
3, Black Ghost Knife fish
6. Discuss fish
7. Giant Gourami's
8. Green Terrors
So enjoy choosing your fish and make a good freshwater aquarium :)