Nano Reef Tank Fish

Top 5 Fish For Pico Aquariums

Top 5 Fish For Pico Aquariums

One question that many reefers ask when they set up a pico tank (such as the Reef Casa Flat 6) is “what fish can I keep in a small reef tank?  Some characteristics that make for great pico tank residents are fish that are: Small, easy to feed, peaceful and don’t require a large amount of swimming space.  With these criteria in mind here is a list of 5 great fish choices for a pico reef tank.  This is by no means an exhaustive list and there are lots of other great options for a small reef tank.  With that being said, let’s take a look at the list!

Yellow Watchman Goby

The Yellow Watchman Goby definitely meets all of the above criteria.  It stays relatively small, is peaceful and will accept a wide variety of prepared foods.  It doesn’t require a lot of swimming space and will spend much of its day moving slowly around the sandbed or perching on rock ledges.  Not only that, but it has an amusing facial expression and a personality that will keep hobbyists engaged for hours!  Pair one with a pistol shrimp to observe one of the most interesting symbiotic relationships in the reefing hobby.

Tail Spot Blenny

This small blenny is unmistakable with its large eyes and tiny mouth.  Combine this with an inquisitive personality and you have the perfect pico reef fish.  They prefer to spend most of their day perched on rock ledges or on corals and have a trademark watchful expression.  They will happily eat a variety of prepared foods and will also graze for algae on the rockwork, making them both interesting and useful.  They are known to be jumpers, so a tight fitting lid is recommended.

Ocellaris Clownfish

The Clownfish is a staple in the reefing hobby and can be housed singly in a pico aquarium.  They come in a wide variety of designer colors, as well as the standard orange and white.  They are generally peaceful but may become territorial over time.  For this reason, any tankmates in a pico tank should be carefully chosen.  They are hardy, easy to keep and will accept a wide variety of prepared and frozen food.


Hectors Goby

The Hectors Goby is a great choice for a pico tank and is both interesting to look at and useful.  It has an elongated, bluish-black body with bright yellow horizontal stripes and an eyespot on the dorsal fin.  It prefers a tank with ample hiding spots, as well as rockwork for grazing.  In addition to consuming a wide variety of prepared foods it will also make itself useful by feeding on nuisance algae and worms.

Geometric Pygmy Hawkfish

The last fish on our list is less well known (and a bit more expensive) than the previous four but makes a great choice nonetheless.  They rarely grow larger than 2” and are generally peaceful, although they will sometimes behave aggressively to other bottom dwelling fish such as some gobies and blennies.  They can be fed a variety of prepared and frozen foods and make a unique choice for a pico tank.


While the size of a pico tank does somewhat limit fish choices there are lots of great options for small aquariums.  The key is to research carefully and choose generally peaceful fish that inhabit different areas of the tank to avoid aggression.  If you have any questions about fish choices for your pico reef tank please send us an email, we are here to help!