Nano Reef Tanks and Fish Size

What fish can you keep in a nano reef aquarium?

Q. Is it possible to keep surgeonfish in a nano reef aquarium? When I was at MACNA this year I was surprised to see lots of nano aquariums with small surgeons in them. Is this common, and is it possible for this to be successful in the long term?
Jared M.
Pittsburgh, Pennsylvania

A. I too noticed a lot of small aquariums housing surgeonfish at the MACNA show. Some of these aquariums had small bristletooth tangs in them while others housed very small yellow tangs. My guess is that the displays we saw during MACNA were for eye appeal only as many of the tropical fish in those aquariums were for sale or a prize for one of the many raffles. I don’t think the goal of those displays was to encourage people to keep surgeonfish in a nano reef environment because it’s practically impossible and will most certainly make for a huge failure in the long run.

Juvenile surgeonfish can be very misleading from a size standpoint. Many aquarists purchase surgeonfish for larger aquariums and soon realize that these tropical fish attain lengths of 12 inches or more with an impressive body mass. Adult surgeonfish of most any species are large tropical fish that require open swimming space with little to no obstructions. I personally did not realize the sheer size and swimming capabilities of these fish until I was diving in natural reef ecosystems and observing them in action.

As far as keeping surgeonfish in nano reef aquarium, the displays at MACNA were the first I’ve seen that housed surgeons. Most nano reef aquariums keep a small population of fish that don’t attain lengths in excess of 3 inches. I have found that the best success can be had when a nano reef aquarium is kept with one or maybe two small tropical fish, allowing the invertebrates to really be the stars of the show.

Fish, even small ones, have quick metabolisms and produce enough waste to degrade water quality in small saltwater aquariums. Invertebrates on the other hand have painfully slow metabolisms and don’t create near the waste that fish do. In short, a few tropical fish and lots of invertebrates and corals is the way to go. The thought of keeping a surgeonfish in a nano reef aquarium for the long term is almost crazy. There is just no way, even with daily water changes, I can see that working out. It would be a very cruel practice for the tropical fish.

While I think nano reef aquariums can make for a good introduction into the hobby, because they require more diligent care and attention to detail than some larger automated systems, they also make it possible for beginning aquarists to make detrimental mistakes. The organizers that had the displays at MACNA probably assumed that most people attending the show were reasonably advanced aquarists and would be able to realize that keeping a surgeonfish in such small quarters was a bad idea. I will say that if you had a large nano aquarium, (24 to 30 gallons) and a large reef aquarium and wanted to house a very small juvenile tang in the nano, only long enough for it to attain a size better suited for the larger aquarium then and only then would the practice be appropriate. I have purchased small Atlantic blue tangs and housed them in 20-gallon nano aquariums so that I could easily provide them with algae-rich fish foods and allow them to fill in. As soon as the fish grew large enough it was moved to the main display aquarium.

I would recommend looking at the cherub angelfish (Centropyge multicolor) as a possible tenant if you are planning on starting a nano reef aquarium. These Caribbean dwarf angels stay rather small, not exceeding 3 inches, and are colorful and active members of a nano reef community. They are unique in the nano reef aquarium because they have the same body style as larger saltwater angels, but lack the size or waste producing potential of their larger cousins. Just be advised, like any angelfish they have the potential to nip corals.

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Fish · Reef Tanks