We’ll explore some exciting options for species-only tanks. Species-only setups offer a unique feel, and many featured fish are popular choices among aquarists. This guide covers species-only tanks organized by size, ensuring options for every aquarium.

Prepping for Your Tank Setup

Before we dive into the list of inhabitants, here are two quick notes:

1. For single-fish setup inspiration, check out Joanna’s video linked in the description. It’s worth a look for inspiration.
2. If you want more information about the fish featured in this article, Check the links provided for species profiles and care details. You’ll find species profiles and care details.

The 5-Gallon Aquarium

Let’s start small. If you’re new to fishkeeping, keep in mind that smaller aquariums, like a 5-gallon tank, can be harder to regulate in terms of water parameters. For experienced fishkeepers, though, here are some cool options:

• Shrimp:
  Shrimp make excellent species-only aquarium inhabitants. They stay tiny, are highly active, and come in various colors. Popular choices include blue dream, cherry, and pumpkin shrimp. If you choose shrimp, I recommend sticking to one color type, especially with Neocaridina, as mixing colors often results in hybrid offspring with dull, brownish shades.
• Florida Least Killifish (Heterandria formosa):
  These are among the world’s smallest freshwater fish, with females reaching about ¾ of an inch and males about ½ inch. They are active, peaceful, and perfect for a 5-gallon tank. Despite their size, they bring plenty of personality and include a stunning gold variety.

The 10-Gallon Aquarium

You can keep all the species mentioned above in a 10-gallon tank and add more individuals. Here are additional options:

• Guppies and Endlers:
  Guppies are full of color and activity. They are colorful, active, and breed easily. Start with a couple of males and 6–8 females for a vibrant setup.
• Tiger Limia:
  This uncommon livebearer has a fun personality and a unique greenish-gold sheen.
• Rice Fish:
  These small fish have shiny, iridescent colors and display fascinating behavior, like carrying eggs attached to their anal fins.

The 20-Gallon Aquarium

For a 20-gallon tank, consider cichlids:

• Shell-Dwelling Cichlids:
  Species like Neolamprologus multifasciatus (Maltese) and N. brevis stay small and exhibit fascinating behaviors like rearranging sand and shells.
• Rock-Dwelling Cichlids:
  Options like Julidochromis ornatus and J. transcriptus have striking colors and patterns. These fish are territorial but thrive in species-only setups.

The 40–55-Gallon Aquarium

Two standout options for this range are:

• Pearl Gourami:
  These peaceful fish have gorgeous coloration and can be kept in groups, unlike other gouramis.
• Mbuna Cichlids:
  Species like Pseudotropheus saulosi and rusty cichlids are colorful, less aggressive, and perfect for mid-sized tanks.

The 75-Gallon Aquarium

Larger tanks bring more options:

• Electric Blue Acara:
  These peaceful cichlids have striking blue coloration and do well in groups.
• Goldfish:
  Fancy goldfish are perfect for a 75-gallon setup. They’re hardy, peaceful, and don’t require heated water.

Other options include Midas cichlids and flowerhorns, which are best kept alone due to their size and aggression.

The 125-Gallon Aquarium

For a six-foot tank, consider these showstoppers:

• Oscars:
  These large, colorful cichlids are personable and active. A 125-gallon can house 2–3 Oscars comfortably.
• Peacock Cichlids:
  An all-male Peacock Cichlid tank offers breathtaking colors but requires careful aggression management.
• Geophagus:
  Species like G. altifrons or G. steindachneri are peaceful, colorful, and perfect for larger tanks.

Key Information

Conclusion

Species-only aquariums allow fish to display their natural behaviors, creating a more enriching and visually stunning experience. Choose fish suited to your tank size and water parameters to enjoy the unique dynamics of a species-only setup.