Nano Reef Fish--Part 1

[Anonymous]

Here is a catalog of fish that I feel can be suitably kept in tanks as small as 30 gallons, some even smaller. The purpose of this list is to serve as a starting point for selection, rather than an all encompassing husbandry guide. PLEASE research any particular fish species thoroughly before purchasing to determine its particular requirements.

Some of the fish species here should be housed as the only fish in the system, either due to bioload, aggression, or outright predation. In particular, the angelfishes, hawkfishes, eels, frogfishes, some dottybacks, and some wrasses should be strongly considered as the sole fish in a nano tank, unless otherwise noted. The adult size, behavior, and temperament of any fish should be carefully considered before placing it in your tank.

Unfortunately there are many species offered for sale that consistently fail to thrive in controlled conditions due to several factors such as specialized diets or habitats. I cover these here and note their difficulty, as a warning to those tempted to purchase them.

The adult size of any nano candidate should be carefully considered. Although thumbnail sized juveniles of large fish like these Paracanthurus hepatus will fit in a nano, they will quickly outgrow it. Juveniles this small ship and adapt poorly to captivity as well.

When selecting a fish for a reef tank of any size, I consider several things to determine the suitability of the fish to the tank (and vice versa!):
Water quality--will I be able to maintain coral reef quality water with the fish in a particular volume? How much food can I add on a daily basis and expect to keep water quality high? How often will I need to do water changes? These are questions best answered by past experience in the marine aquarium hobby. My best advice is to always underestimate the amount of fish you can keep in a given volume, especially in smaller tanks.
Tankmates--how will the current or future resident fish behave towards the fish? Will the fish prey on the other animals in the tank, or behave aggresively towards them?
Habitat selection--where does the fish come from, and how can I design the tank best to suit its needs? Does it need a large surface area of sandy bottom? Does it need a sand bed at all? Will it feel more secure in a tank filled with live rock, or one with ample swimming space? Will dim light levels increase the likelihood it will acclimate well? Keep in mind that the ideal habitat for some fish is not the best habitat for others. The tank should be designed around the fish, rather than attempting to make several fish "fit" into an unsuitable tank.
Feeding--what will I feed the fish? What foods provide the best nutritional value? Will a refugium aid in providing the fish a constant food source? Will I need to culture live food for my fish, and how much work will that entail? There are several recipes for home made foods available on the internet. Among the more nutritious foods for carnivores are Cyclop-eeze, newly hatched baby brine shrimp enriched with an algal paste, frozen mysid shrimp (especially "Piscine Energetics" brand), fish eggs, fresh chopped table shrimp, fresh squid, clam, or crab meat, and live ghost shrimp or fiddler crabs fed a diet of the same. All meaty frozen food (especially mysis shrimp and Cyclop-eeze) should be rinsed thoroughly before adding to the tank. For herbivores, a bit of microalgae can easily be encouraged to grow. Chopped spinach and broccoli is sometimes accepted, as well as flake or frozen foods containing Spirulina. Sheets of unsalted dried seaweed (aka nori or wakame) are usually accepted, and live Ulva, Gracillaria, and Chaetomorpha species are easy to cultivate and make great herbivorous fare.
Note: A widely mis-used (in my opinion) food in the aquarium hobby is unenriched adult brine shrimp (live or frozen), as it has a very low nutritional value. Live brine shrimp that are enriched with a phytoplankton and/or HUFA supplement for several hours before feeding can be a valuable part of a varied diet.

Where does one find out all this information, anyhow? Here are some good places to start:
The Reef Fishes Volumes of books by Scott W. Michael are far and away the most inclusive husbandry manual for coral reef fishes available.
Coral Reef Fishes by Ewald Lieske and Robert Myers includes info on diet, habitat, size, and range for nearly all available species found in the marine aquarium trade, although there is very little husbandry information.
Field Guide to Anemone Fishes by Daphne Fautin and Gerald Allen
Seahorses, Pipefishes, and Their Relatives by Rudie Kuiter
Fairy and Rainbow Wrasses by Rudie Kuiter
Fishbase.org
Advanced Aquarist Online Magazine
Reefs.org
Reefkeeping.com
Zipcodezoo.com

If you would like me to add a fish to this list that you don't see here or have any other comments or questions, feel free to email me at [email protected]

Happy Fishkeeping!
Matt Wandell
Steinhart Aquarium,
California Academy of Sciences

 

[Anonymous]

Angels

Of all the genera in the family Pomacanthidae, only one is truly suitable for inclusion in a nano reef: Centropyge.

There is some taxonomical confusion about the genus Paracentropyge, but I most often see it to include three species--P. multifasciata, P. venusta, and P. boylei. All are from deepwater, rare, expensive, and none adapt well to captivity.

If you value your corals more than life itself, don't get a Centropyge angel. There is always some risk involved when keeping them with corals or clams. Some species are a bit less risky while others are almost a guarantee to nip at anything and everything. Most open brain corals (Trachyphyllia, Lobophyllia, Symphyllia, etc.) in particular seem to be particularly prone to being "tasted" by Centropyge angels, as well as some large fleshy polyped stony corals (Euphyllia, Cynarina, Scolymia Caulastraea, Blastomussa etc.) On the other hand, anemones, leather corals, zoanthids, and mushroom corals are usually ignored.

In general, Centropyge angels will not tolerate members of the genus in the same tank (at least not a 30 gallon, that's for sure!). Some can be aggressive towards other substrate pickers. Angels are, for the most part, ignored by even more aggressive fish.

All Centropyge angels should be kept in a mature tank, and offered an omnivorous diet with large amounts of algae.

Caribbean Pygmy Angel, Centropyge argi (3.1")
Photo Copyright John E. Randall

Along with C. aurantonotus, C. acanthops, and C. resplendens, this fish forms the "argi" complex. These fish are all among the least likely to nip at corals, yet can be very aggressive towards smaller fish. C. argi has spawned in captivity, and can be kept in a tank as small as 10 gallons.

Coral Beauty, C. bispinosa (3.9")
Photo Copyright Robert Yin

The Coral Beauty is one of the hardiest members of the genus. It is moderately risky with corals. It is one of the least aggressive members of the genus towards smaller fish.

Flame Angel, C. loricula (3.9")
Photo Copyright John E. Randall

Recently, captive bred specimens of this fish have become available. Flame angels are moderately risky to keep with corals. They are one of the most peaceful angels towards other smaller fish, and are one of the hardier members of the genus.

Fisher's/Whitetail Angel, C. fisheri/flavicauda (3.0")
Photo Copyright recif-france.com

Photo Copyright John E. Randall

These species are considered by many to simply be color morphs of the same fish. They are among the smallest of the Centropyge. I have only kept C. flavicauda. It was in a fish only tank with a royal gramma, chromis, and a coral beauty angel, where it behaved peaceably and adapted readily to prepared foods.

 

[Anonymous]

Anthias

Most of the commonly encountered species from your local fish store in the family Anthiidae come from the genera Pseudanthias and Nemanthias. The majority of these species grow too large and need too much swimming space to be placed in a system as small as 30 gallons, but some smaller anthias may benefit being in a smaller tank with less aggressive tankmates and competitors.

All anthias species will require frequent feedings of small food, and many do not adapt easily to prepared foods and may require live food initially. I would strongly suggest only advanced fishkeepers attempt any of these fish in a smaller tank. The more difficult anthias will benefit from an auto feeder or drip of live enriched Artemia nauplii and adults along with regular feedings of cyclop-eeze, Arcti-pods, fish eggs, live mysis shrimp, chopped or whole frozen mysis, and very small particles of chopped krill, prawn, clam, or squid flesh.

In general the anthias can be kept in mixed sex harems with one male per several females but this is difficult in small tanks. In most cases it would be best to keep these fish singly in a nano.

Sunset Anthias, Pseudanthias parvirostris (3")
Photo Copyright Lisa D./www.aquahobby.com

Among the Pseudanthias this is one of the hardier choices. It will readily consume most prepared food and adapts well to captivity. The only downside is that it is an aggressive fish that may harass other anthias and zooplanktivores such as firefish and flasher wrasses.

Randall's Anthias, Pseudanthias randalli (2.5")
Photo Copyright Y. Otsuka

This is a deepwater anthias with a stunning male coloration. It is moderately difficult to get feeding, and is moderately aggressive towards other zooplanktivores.

Ventralis Anthias, Pseudanthias ventralis (2.5")
Photo Copyright Mark Poletti, from Matt's tank.

This is an incredible deepwater anthias with an absolutely dismal rate of survival in captivity. I would strongly suggest only advanced anthias keepers attempt to try it. It especially suffers from decompression related issues and shipping stress, and is extremely shy and reluctant to feed on anything but live foods initially. Low light levels and water temperature in the low 70s will help it acclimate.

Fathead or Sunburst Anthias, Serranocirrhitus latus(5.1")
Photo Copyright John E. Randall

The Sunburst Anthias is moderately difficult to get feeding and is not very aggressive towards anything but conspecifics. Scott Michael wrote a great article about S. latus HERE.

Slender Anthias, Luzonichthys spp. (2.0 - 3.0")

The Slender Anthias generally fail to acclimate to captivity. They will benefit from frequent feedings of small live food and peaceful tankmates but are very shy and tend to suffer from sudden and unexplained mortality.

Basslets
"Basslet" is sort of a catch-all term, and I'm going to include some species that aren't really taxonomically related. If you're a biologist, please forgive me. However, these fish all have a similar appearance and body shape, and are commonly grouped together by fish wholesalers and retailers. All the basslets should be considered somewhat of a threat to any smaller shrimps or fish small enough to fit in their mouth. They are all relatively hardy fish that acclimate well to aquarium life, and should be fed frozen mysis, clam, prawn, krill and other meaty foods.

Candy Basslet, Liopropoma carmabi (3.0")
Photo Copyright Gregory Schiemer

This is an absolutely stunning fish but nearly impossible to obtain because of its limited range in very deep water. If it is available, you will pay a fortune for it! Its husbandry is similar to the other Liopropoma spp.

Swale's Basslet, Liopropoma swalesi (3.0")
Photo Copyright Tristan Lougher

This is an awesome fish! They are very secretive and peaceful towards other fish, but make a stunningly beautiful centerpiece in a small tank. It can easily be distinguished from L. carmabi by the presence of a black spot with white margin on the anal fin. L. carmabi lacks this ocellus. This fish will appreciate a more dimly lit tank, and will come out more often if kept with peaceful dither fish such as dartfishes (Nemateleotris or Ptereleotris spp.) or assesors.

Swissguard Basslet, Liopropoma rubre (3.1")
Photo Copyright Adrian Marsden

A bit more commonly seen than both of the above species in fish stores, yet still commands a high price. The care is similar for both. These two species can be put in the same large tank, but it is probably best to keep singly in a nano. There are several other rarely offered and stunning Liopropoma spp. and all make suitable nano candidates. Some (such as L. eukrines) can grow quite large so be sure to check the maximum size of the species you are purchasing.

Chalk Bass, Serranus tortugarum(3.1")
Photo Copyright John E. Randall

A peaceful little planktivore that can be kept in groups. It will spend most of its time hovering in the open.

Harlequin Bass, Serranus tigrinus (3.9")
Photo Copyright Robert A. Patzner

An aggressive species that will devour small shrimp and tiny fish.

Royal Gramma, Gramma loreto (3.0")
Photo Copyright Robert A. Patzner

A beautiful and hardy fish. They can be kept in pairs or groups in larger tanks, but it is probably wise to keep singly in small tanks. They can be aggressive towards smaller peaceful fish. Can be kept in tanks as small as 10 gallons.

Geometric "hawkfish" or perchlet, Plectranthias inermis (2")
Photo Copyright Tristan Lougher

The Plectranthias spp. are typically sold as hawkfish by retailers, since they look and act like them. They are, in fact, from the Anthias family. I treat them here as basslets because they look and behave similarly. They stay small and are ideally suited for a nano tank. They will consume very small ornamental shrimps.

Pelicier's Perchlet, Plectranthias pelicieri (2.0")
Photo Copyright Jake Adams

This is an unbelievably beautiful fish that is only rarely imported into the US. Its husbandry is identical to the above fish.

Yellow and Blue Assessor, Assessor flavissimus and A. macneilli (2.4")
Photo Copyright Robert Fenner

Photo Copyright Robert Fenner

Great fish! These little beauties are captively bred by the folks at ORA (http://www.orafarm.com) They are incredibly peaceful, hardy, and completely reefsafe. They can be kept in groups of 3 in a tank as small as 20 gallons if added simultaneously. Assessors rarely hide, will often swim sideways or upside down, and will also appear out in the open after the lights are off. They will squabble by facing head to head and opening their mouths at each other, but rarely fight to the point of injury. Can be pricey but well worth it.

Banded Spiny Basslet, Belonepterygion fasciolatum
Photo Copyright John E. Randall

I only include this one as a warning to not buy it. You will most likely see this fish two times--when it's at the store, and if you completely dismantle your tank to move it. It will hide when you let it out of the bag, and then you'll never see it again. They are very beautiful, and apparently do well in tanks with abundant live rock but are so secretive that they make terrible aquarium fish. I kept this fish for at least a year, assuming it had died shortly after introduction, only to find it alive and well when I moved the tank it was in.

Eastern Hulafish, Trachinops taeniatus (4")
Photo Copyright Richard Ling

The Trachinops spp. are all found in temperate waters in Southern Australia and Tanzania where they form mixed-sex shoals and feed on zooplankton. Although this species is found in warmer water than the other Trachinops spp., they do not occur in waters warm enough year-round to support coral reefs. I have no information on how well this fish will adapt to the temperature of a reef tank.

 

[Anonymous]

Anemonefishes or Clownfishes
The anemonefishes suitable for tanks smaller than 20 gallons are found in the genus Amphiprion. Most are easily maintained and will readily accept prepared foods in the aquarium. With a few exceptions, all the anemonefish will do just fine without a host anemone. In fact, I recommend NOT keeping any host sea anemone in a nano tank unless you are a very experienced aquarist. Anemonefish can be easily paired by selecting two juveniles and simply adding them to the tank at the same time. If adding a clown to a tank with an established clown, add a smaller juvenile to the tank. Much more info on Anemonefish behavior, pairing, and breeding can be found in Joyce Wilkerson's excellent book "Clownfishes".

Anemonefishes are generally fairly peaceful, but will sometimes quarrel with congeners (members of the same genus) and with the closely related damselfishes. All should be fed a diet of frozen mysis and meaty foods. Clowns will graze a small amount of microalgae from the live rock in a mature aquarium.

Virtually every common species of Amphiprion can be found captively bred, and I strongly urge all fish keepers to buy captively bred fish whenever possible.

Although Clark's, Tomato, and Maroon clowns (A. clarkii, A. frenatus, and Premnas biaculeatus) are commonly available and look cute when small, all will outgrow tanks smaller than 30 gallons at a mature size and can be quite aggressive to other fish (and human hands!) in small tanks. I suggest the following species for a nano tank:

Clown anemonefish, Amphiprion ocellaris and A. percula (3.9")
Photo Copyright John E. Randall

These are the "Nemos" that have sold many a fish tank to novice fishkeepers. Very peaceful, and hardy. Of the two species, A. percula is slightly more aggressive. A. ocellaris can be kept in trios or groups in larger tanks, but I have never tried it in a small tank. Highly prized "Black Percula" clownfish are actually a variant of A. ocellaris from found in a small area near Darwin, AU.

Pink skunk anemonefish, Amphiprion perideraion (4.1")
Photo Copyright Robert A. Patzner

A very peaceful and delicate anemonefish that will appreciate passive tankmates and lots of hiding places. Will likely do better with the addition of a hardy "surrogate host" coral, such as a Sinularia, Nephthea, Euphyllia spp. May need a bit of live brine to commence feeding. Definitely a less hardy choice than either A. ocellaris or A. percula.

 

[Anonymous]

Dottybacks
Ah, the little dottybacks. The family Pseudochromidae is for the most part an incredibly hardy and aggressive group of fish. I've only listed a few of the more common and desirable members of the genus Pseudochromis here. Virtually all the Pseudochromis spp. will work in a nano, although I suggest getting a correct species ID and determining the adult size before purchase. Some of the larger species get to be 5" or longer and would need larger quarters when fully grown. Some of the nicer choices are P. springeri, P. tonozukai, P. splendens, and P. flavivertex.

With the exception of P. fridmani and P. sankeyi, all the dottybacks should be considered a threat to any small fish, shrimp, snail, or crab. Most will also prey on polychaete bristleworms. All will readily accept prepared foods. Unless a breeding pair is obtained, all the dottybacks besides P. fridmani and P. sankeyi should be kept singly and without any other fish tankmates, preferably.

All the dottybacks are great jumpers, and their tank should be well covered to prevent carpet surfing.

Most of the members of the genus Pseudochromis are available captively bred, and should be purchased as such.

Arabian dottyback, Pseudochromis aldabraensis
Photo Copyright Robert Fenner

This fish can be an absolute terror, even in large tanks. I had one that chased an established firefish into hiding in an 80 gallon tank after being in the tank for about 30 seconds. It should probably be kept by itself in any nano.

Striped dottyback, Pseudochromis sankeyi
Photo Copyright John E. Randall

This fish is on the lower scale of aggression among the dottybacks, and can be kept with semi-peaceful fish in small tanks. It is also possible to create pairs by adding two fish simultaneously.

Orchid dottyback, Pseudochromis fridmani
Photo Copyright Robert Fenner

Photo Copyright John E. Randall

(Probable male. Note lower edge of tail fin.)

Far and away my favorite dottyback. This fish is usually peaceful even with passive fish such as flasher wrasses and chromis. The sexes can be easily distinguished by the appearance of the tail. Males have a tapered streamer at the bottom of the tail, while females have a rounded tail. Male/female pairs can be kept in tanks as small as 20 gallons.

Royal dottyback, Pseudochromis paccagnellae
Photo Copyright Robert Fenner

A little terror of a fish that will attack any other tankmate kept with it in a nano, and even in large tanks. Watch your hands!

McCulloch's dottyback, Cypho purpurescens (3.0")
Photo Copyright John E. Randall (male in foreground)

This is a rare, aggressive, and stunning fish. Its care is similar to the Pseudochromis spp. Male-female pairs can be kept in large tanks but it is probably best to keep singly and without any other fish tankmates in a nano.

 

[Anonymous]

Wrasses
All the wrasses listed here will accept frozen mysis and other meaty foods. The Wetmorella, Paracheilinus, and Pseudocheilinops spp. are all peaceful except to congeners. All the Pseudocheilinus spp. can be quite aggressive to fish and crustacean tankmates.

All the wrasses should be considered potential jumpers and their aquarium should have a completely enclosed canopy or cover. I have read countless tales on this BB of folks' wrasses who were thriving yet died because they didn't take the time to put a cover on their tank. Don't make this mistake!

None of the wrasses listed here require a sandbed to bury in, although all will benefit from the microfauna associated with one. Those species listed here will readily acclimate to a bare bottomed tank.

Flasher wrasses, Paracheilinus spp. (2.5-3.5")
All Paracheilinus Photos Copyright Hiroyuki Tanaka

P. mccoskeri

P. lineopunctatus

P. filamentosus

P. filamentosus is the most commonly sold member of this perfect reef tank group. All members of the genus Paracheilinus will readily accept food, are completely reef safe, and will only rarely pester tankmates. These can and should be kept in groups of 2-3 fish, with peaceful tankmates and preferably before any other fish are added. They ship poorly but once acclimated will become quite hardy and will accept most prepared foods. Since they are zooplanktivores they should be fed small amounts of food frequently. More information on the flasher wrasses can be found HERE.

Sixline wrasse, Pseudocheilinus hexataenia (4.0")
Photo Copyright John E. Randall

The sixline wrasse is a very commonly available fish and makes a great nano candidate. It may prey on small snails,a benefit if one is attempting to control paraistic pyramidellid snails. It can become quite aggressive to other fish. It should be considered a threat to Lysmata and Stenopus spp. shrimp as well.

Five Bar or Mystery Wrasse, Pseudocheilinus ocellatus (4.7")
Photo Copyright John E. Randall

This fish commands a high price, yet shows up in aquarium stores more and more frequently. Similar to the sixline wrasse, it can be quite aggressive to other fish and may prey on shrimp and small snails. If you don't mind the price tag, it makes a beautiful centerpiece. Should be kept singly in a nano. Scott Michael wrote a great article about this wrasse that can be viewed HERE.

Arrowhead Wrasse, Wetmorella spp. (3.0")
Photo Copyright John E. Randall

A secretive, peaceful little genus. They show up occassionally in retail stores, usually with a high price. They get along with other peaceful wrasses provided they are added first. There should be a multitude of hiding places and caves in the tank to make this fish feel secure. Scott Michael wrote a great article about this genus that can be viewed HERE.

"Pink" or "Cryptic Sixline" Wrasse, Pseudocheilinops ataenaia (2.5")
Photo Copyright John E. Randall

A monotypic genus. This fish is very secretive and will do best if housed in a tank with abundant caves and hiding places and with peaceful tankmates. It should not be kept with Pseudocheliinus spp. but can be kept with Paracheilinus and Wetmorella spp. Similar in care to the Wetmorella spp.

 

[Anonymous]

Hawkfishes

Hawkfishes make endearing little additions to a nano tank. They will find a nice place to perch and keep an eye on the entire tank, then dart out to eat passing food. They have excellent eyesight (thus "hawk") and will watch you as you move about the tank.

All should be considered a threat to very small fish, snails, and shrimp. They can behave aggressively to passive fish, and are most likely kept best singly in a nano.

Hawkfishes are one of the few groups of bony fishes that have no swim bladder, so they sink unless they constantly swim. What this means is that they will constantly sit on corals and clams, and in a nano this may irritate the invertebrates. It rarely becomes a problem, but it's something to consider.

Falco Hawkfish, Cirrhitichthys falco (2.8")
Photo Copyright Marietta van der Werff

One of the smallest of the hawkfishes, with the best personality in my opinion. Its small size makes it a threat only to very small shrimp and fish.

Flame Hawkfish, Neocirrhites armatus (3.5").
Photo Copyright John E. Randall

Can be quite aggressive to other fish and will consume many desirable invertebrates other than corals. It does, however, make a striking display.

Longnose Hawkfish, Oxycirrhites typus (5.1")
Photo Copyright John E. Randall

A deepwater hawk that ocassionally makes its way into fish stores. It rests on gorgonians in nature. Adding a synthetic or living gorgonian to its tank makes for an impressive display.

 

[Anonymous]

Blennies
The blennies make endearing and fascinating additions to a small tank. Although some are well known as great algae eaters, the family has a few members that feed almost exclusively on plankton and ignore algae. As always, the diet and behavior of each species should be thoroughly researched before purchase.

A note about the Lawnmower Blenny, Salarias fasciatus--I feel this fish, although incredibly fascinating and endearing, is best kept in a larger system. They get quite big (5.1"), can become aggressive to tankmates, and need a lot of microalgae present to thrive. In my experience they are reluctant to accept substitute foods. If you add a small one to a nano, please have larger future accomodations ready for it. Special attention should be paid to the stomach of the fish. If it is getting pinched, it's not getting enough to eat. A properly fed lawnmower blenny will have a nice full belly.

Bicolor Blenny, Ecsenius bicolor (3.9")
Photo Copyright Robert A. Patzner

A mostly peaceful little species if kept with medium-aggressive tankmates (pygmy angels, Pseudochromis fridmani), but can be aggressive to firefish, small gobies, etc. It should be offered plenty of omnivorous foods and microalgae. This fish has been known to peck at SPS corals on occasion. There are several other Ecsenius spp. blennies (some are even being captive raised) that all would do well in a nano with similar care. Most are in the range of 2-4" as adults.

Mimic Blenny, Ecsenius gravieri (3.1")
Photo Copyright Richard Field

I've only casually observed this fish in other folk's tanks, and it seems pretty similar to E. bicolor in behavior. This fish mimics Meiacanthus nigrolineatus. According to Greg Schiemer this fish may rasp at SPS corals and damage them.

Midas Blenny, Ecsenius midas (3.9")
Photo Copyright Richard Field

The Midas Blenny is a bit atypical of the genus in that it spends most of its time in the water column picking at zooplankton and mostly ignores algae. It can be aggressive to other planktivores, so choose tankmates accordingly. It should have plenty of swimming space available.

Yellowtail Fang Blenny, Meiacanthus atrodorsalis (4.3")
Photo Copyright John E. Randall

The beauty of this fish speaks for itself. All the Meiacanthus spp. should be kept in a larger nano tank with plenty of swimming space, and offered small meaty foods such as frozen mysis shrimp. They are planktivores and will mostly ignore other tankmates, with the possible exception of firefish and dart gobies. M. bundoon is a similar species that is available captively bred.
IMPORTANT: All the Meiacanthus spp. have a pair of venomous fangs that they can and will bite you with. Handle with extreme caution.

 

[Anonymous]

Cardinalfishes

There are countless species in this family that could potentially work in a nano, so I will only list some of my favorite species. All cardinalfishes are quite hardy once established, although many are poor shippers. All are a threat to very small fish or shrimp that will fit in their enormous mouths. Cardinalfishes are mouth brooders; the male holds fertilized eggs in his mouth until the young are ready to hatch. Several of these species will spawn readily in captivity and some species have been successfully reared from eggs.

Blue eye Cardinal, Apogon leptacanthus (2.5")
Photo Copyright John E. Randall

According to Charles J. Devito: "Just about the perfect fish. Also called the glass or threadfin cardinal. A true schooling fish, it will school even in small tanks. They are shy but gradually gain a bit of boldness if nothing in the tank will bother them. Hearty eaters, hardy fish, breeds easily in captivity. A group of 3-4 would definitely be okay in a 20 gallon."

Red Lined Cardinal, Apogon margaritophorus (2.5")
Photo Copyright K. Uchino

The Red Lined Cardinal is a hardy and bold fish. It does quite well in groups and will accept virtually any prepared food offered.

Seale's Cardinal, Apogon sealei (4")
Photo Copyright Phillippe Poppe

The Seale's Cardinal is an absolutley stunning fish that is incredibly hardy and will do well in small or large groups. Be aware that it gets a bit larger than some of the other cardinals listed here and so will need a bit larger tank when full grown. This fish will spend its time in full view even in bright light.

Banggai Cardinal, Pterapogon kauderni (3.0")
Photo Copyright Grégoire Germeau and Yves Doumont

This fish is threatened with extinction in the wild, due to collection by the aquarium trade. Thus, it's a really really bad idea to buy a wild caught one. Please don't! Fortunately this fish spawns quite readily in captivity, and the young are relatively easy to raise on newly hatched gut loaded baby brine shrimp, Cyclop-eeze, and small frozen mysids. If you want one or two of these fish, please find a captive bred source! Although juveniles can be kept in groups, adults tend to pair up and beat up smaller individuals in aquariums.

 

[Anonymous]

Damsels

It seems that every beginning fish keeper has probably owned a damsel as a first fish, and then later curses their very existence. The Family Pomacentridae has several members that are very cute as juveniles but grow into large, aggressive, and drab adults. These include the commonly seen genera Neoglyphidodon, Stegastes, and Abudefduf, among others. Some members of the genus Pomacentrus are borderline suitable for nanos, although they are almost all highly aggressive. Fortunately, there are several species in the genera Chromis and Chrysiptera that stay beautiful as adults, stay rather small, and can be included in a properly selected community of fish. All of the species listed here will readily acclimate to aquarium life, accept prepared foods, and stay small. Chromis spp. feed on zooplankton in the wild, and Chrysiptera spp. feed on zooplankton and supplement their diet with a bit of microalgae. Please be aware of the damsel species you are purchasing! Some of them get quite large as adults, and many look very similar.

Blackbar Chromis, Chromis retrofasciata (2.0")
Photo Copyright Adam Cherson

The smallest of the commonly sold Chromis genus. Chromis are peaceful towards almost all unrelated fish, but will squabble with each other. This species in particular can be very aggressive to the smaller individuals in a group. Adding a shoal of a dozen or so individuals can reduce this aggression in larger tanks, but this is not advisable in a nano. These fish can be kept in pairs, although it is tricky. You have to select a pair that appears to get along out of a group. Care for nearly all other Chromis spp. are identical.

Vanderbilt's Chromis, Chromis vanderbilti (2")
Photo Copyright Keoki Stender

Yellow-tail Blue damsel, Chrysiptera parasema (2.8")
Photo Copyright John E. Randall

An endearing little fish that can be kept in pairs in an aquarium. It maintains its vivid coloration as an adult. Will be peaceful to all but very passive fish. Shouldn't be kept with dartfish, shrimp gobies, or small flasher wrasses. Easily confused with several other similar looking species, so make sure you are getting this one. I've had good luck pairing this fish on several occasions by placing two very small juveniles in a tank simultaneously. There should be numerous small caves and hiding places.

Starck's Damsel, Chrysiptera starcki(2.8")

Talbot's Damsel, Chrysiptera talboti(2.3")

Taupou Damsel, Chrysiptera taupou(3.0")

Fusilier Damsel, Lepidozygus tapeinosoma(4.0")
Photos Copyright Jack E. Randall

I have not found much husbandry info on these fish but have observed them in small holding tanks. Although these are true damselfish and not fusiliers as their common name suggests, they are much more similar to fusiliers in behavior. They are very active fish that roam over large areas and would likely feel extremely cramped in anything but a very large tank. I would strongly advise against trying to keep them in a nano.

 

[Anonymous]

This is the first half of a 2 part list. To view the second half, including Dartfishes, Jawfishes, Gobies, Pipefish, Moray Eels, Frogfishes, Scorpionfishes, Pufferfishes, Clingfishes, and fish unsuitable for nanos, click HERE