Your average nano tank is below 15 gallons, but some people even consider 30 gallon tanks to be nano systems. Either way on how you view it, this is my top ten list for fish to keep in a nano reef.

  1. Clown Goby – These are a very small species of the goby family getting up to 1½ inches in adult length. These are a very docile breed that adds a splash of color to your tank. They tend to perch on rocks and branching corals, or even stick themselves onto the tank walls. They have this ability due to the modified pelvic fin on their underbelly. The only downside I’ve found with these fish is that they are very hard to keep alive. I can’t figure out if it’s because of my tank environment or my tank conditions. Either way, I’ve gone through three of these gobies, each lasting a max of two weeks.
  2. Basslet – These fish tend to grow to a decent size growing up to around three inches in size and come in a variety of bright colors ranging from and orchid-purple to plain black. They can be semi-aggressive because they tend to territorial toward similar-looking fish or other fish that enter their claimed territory. I have found that chalk basslets tend to be very observant like dottybacks watching every little move made within their view.
  3. Possum Wrasse – This is a docile breed of pygmy wrasse from Indonesia that is known to thrive in smaller aquarium setups. They range from red, dark red, or almost black. Males turn a fiery red when courting females. Color may change according to mood and health as well. When keeping these fish in groups, it’s best to follow the same rule as you do when keeping a group of anthias; one male to a harem of at least three females. Keeping two males should be avoided.
  4. Engineer Goby – When these are juveniles, these fish can be a lively addition. They have an eel-like appearance. When they mature into adults they can grow up to a foot long and live in burrows that they may hardly ever leave. They are also known as convict fish because when they mature, their horizontal black and white stripes become vertical making them look like a convict.
  5. Neon Goby – This goby is a cleaner species meaning it will clean parasites and skin from other fish and even clean the mouth of other, much larger fish. They are peaceful and each a max size of 2″. They will fight each other unless they are a mated pair.
  6. Clownfish – Your classic “Nemo” is known as an Occellaris clown, those are the typical orange with three white stripes. Depending on their size at purchase and the size of tank they are placed in, they can grow up to three inches in length. They can be very peaceful but they become aggressive when they are defending territory, protecting an anemone, or defending their food from others. Clownfish do come in many other shapes and colors. My personal favorite is the Clarkii Clown, they have an orange-yellow body with white stripes that are surrounded by a black border.
  7. Cardinalfish – These fish can come in a variety of colors and sizes depending on the breed. Pajama cardinalfish, for example, are your average Joe sporting the neutral colors of brown,black, olive, white, and a dull red. Banggai cardinalfish are another one of my favorites, they have protruding fins with a bright white body that is striped with black. These are peaceful fish that like to be in schools consisting of at least three members. Cardinalfish are surface dwellers that like schooling together toward the surface of the water.
  8. Chromis – Green/Blue chromis are your typical expendable fish due to their conveniently low price ranging from three to five dollars. They are typically used to make sure your tank is chemically balanced after at least a week of cycling. There are more breeds that are a bit more flashy but come at a higher cost which is anywhere from ten to twenty dollars. I myself have owned two Lemon Chromis for around 5 months and they are still very healthy. Though, the only problem I have had is that they fight because they are two different sizes. What matters is that they’ve never injured each other; it’s harmless chasing.
  9. Dottyback – Dottybacks can get themselves into trouble very easily due to their curious behavior. They will investigate every little crack and crevasse that they’re able to squeeze into, no matter how much trouble it may get them into. I had a Neon Dottyback that would sneak into the burrow of my pistol shrimp, and yet no matter how many times he was snapped at he never learned his lesson. I ended up having to return him because I was worried about him dying by the shrimp due to his curiosity.
  10. Firefish – These are an interestingly shaped fish. The orange morphs have a long protruding dorsal fin that resembles that of a moorish idol. These fish have a gradual fade from a fiery red to a solid white that makes the fish resemble a single flame. There are other color morphs that are purple,rather than orange, and have shorter rounded fins. These are a schooling fish that enjoy being in groups of three or more. Firefish are very docile and tend to be the target of aggressive fish, also because they are a small breed of fish only reaching three inches. These fish are jumpers so a tank with a lid is recommended.
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Harlequin Bass (Basslet)
clarkii-clowns
Young Clarkii Clowns