100+ Hardy Freshwater Fish For Cycling A New Aquarium

Although there are many ways to establish the nitrogen cycle in an aquarium, most hobbyists choose to use so-called "starter fish" for the purpose. Perhaps this is because this method allows the new aquarist to have life in their aquarium while the tank is still new. The key to stocking an aquarium is to be patient! Always remember to start an aquarium with no more than 25% of the total carrying-capacity of the tank. Read our guidelines for stocking an aquarium for more information. Following is a big list of hardy fish for starting a new aquarium.

Anabantids (Gouramis and Relatives)

Dwarf Gourami (Colisa lalia)

• Three-spot Gouarmi (Trichogaster trichopterus)
• Dwarf Gourami (Colisa lalia)
• Pearl Gourami (Trichogaster leeri)
• Moonlight Gourami (Trichogaster microlepis)
• Thick-lipped Gourami (Colisa labiosa)
• Sunset "False Giant" Gourami (Colisa fasciata)
• True Giant Gourami (Osphronemus goramy)
• Kissing Gourami (Pink or Green) (Helostoma temmincki
• Betta (with caution) (Betta splendons)
• Paradise Fish (Red or Blue) (Macropodus opercularis)
• Spike-tailed Paradise Fish (Macropodus cupanus)

The Three-spot Gourami comes in several color hybrids sold as Blue, Gold, Platinum, Snakeskin and Opaline Gouramis. These are all the same species. Dwarf Gouramis are also available in many color hybrids, including the Flame and the Royal Blue varieties.

Of the Gourami species listed here, the Pearl and Moonlight Gouramis are the most sensitive, but we have used both successfully to start a new aquarium.

The True Giant Gourami is a fish that is rarely offered for sale. They get huge, and should not be kept in small aquariums. When Kissing Gouramis "kiss" you are observing a territorial behavior between two males, which can get so violent that they actually try to rip each other's lips off.

We list Bettas here, but caution that they do not make good community tank fish. Either their tails and fins get nipped, or they attack other fish with long, flowing fins such as fancy guppies. Paradise fish are also notorious fin-nippers.

Brackish Water Species

Molly fish

Brackish water fish are species that live in particular habitats where rivers meet the ocean. These habitats include river mouths, lagoons, Mangrove swamps, marshes and other estuarine areas. They are not saltwater fish, and they are also not freshwater. Brackish water is freshwater with about three to six tablespoons of salt added per five gallons of water. Following are some hardy brackish water species:

• Molly (Poecilia species)
• Blue Limia (Limia melanogaster)
• Celebes Halfbeak (Nomorhamphus celebensis)
• Other Halfbeak species (Nomorhamphus species)
• Malayan Halfbeak (Dermogenys pusillus)
• Tiger Datnoid (Datnioides microlepis)
• Spadefish (Chaetodipterus faber)
• Batfish species (Platax species)
• Orange (Red) Chromide (Etroplus maculatus)
• Green Chromide (Etroplus suratensis)

Batfish and Spadefish grow very large, and should be kept in aquariums that are 150 gallons or larger. The Pinnatus batfish should not be kept in ANY aquarium, as they will not usually survive in captivity. Tiger Datnoids are aggressive predators that grow large and will eat almost any fish they can fit into their mouths.

The other brackish water species, including Scats, Anableps, Archers, Glass Fish, Leaf Fish, Ropefish, Puffers, Eels, Gobies, Monos, Flounders, Mudskippers, White-tipped Catfish, and Gars, can’t do well in new tank conditions.

Botias (Loaches and Relatives)

Lohachata (Yo-Yo) Loach (Botia almorhae), Wikimedia.org

• Lohachata (Yo-Yo) Loach (Botia almorhae)
• Weather Loach (Misgurnus anguillicaudatus)
• Chinese Weather Loach (Misgurnus mizolepis)
• Horse-faced Loach (Acatopsis choirorhynchus)
• Rainbow (Blue) Botia (Botia modesta)
• Tiger Botia (Botia hymenophysa)

Most Botia and Loach species are not hardy enough to start a new aquarium. Botias are scaleless fish, and are therefore more sensitive to ammonia. The most popular Botia, the Clown Loach, is definitely not a good starter fish, nor is the Kuhli Loach. Some Botias, such as the Rainbow (Blue) Botia, can become very aggressive and should be watched closely.

Catfish (Corydoras, Pleco, and Relatives)

Panda Corydoras (Corydoras panda)

• Upside Down Catfish (Synodontis contractus)
• Green (Bronze) Corydoras (Corydoras aeneus)
• Leopard Corydoras (Corydoras julii)
• Spotted Corydoras (Corydoras ambiacus)
• Bandit Corydoras (Corydoras metae)
• Skunk Corydoras (Corydoras arcuatus)
• Panda Corydoras (Corydoras panda)
• Mottled Corydoras (Corydoras punctatus)
• Channel Catfish (Ictalurus punctatus)
• Common Plecostomus (Hypostomus plecostomus)

Catfish are not scavengers, to be put in an aquarium to clean up messes. You may have heard that if you keep Catfish and/or a Plecostomus or two, you'll hardly ever need to clean your tank. Nothing could be further from the truth. Catfish do not eat solid fish waste, and very few species can tolerate ammonia or nitrite. They need a steady diet of fish food. While almost all Plecostomus species feed on algae, they too need a varied diet. If you are the type that cleans up all your algae and keeps your tank immaculate all the time, you should not have an algae-eating fish in your tank.

Many different kinds of Catfish are accessory air-breathers and can tolerate relatively low oxygen levels. However, most aquarium Catfish species have not proven very tolerant of ammonia. Do not assume that another species related to one on this list will also be hardy. Even the species listed here are usually best added after the aquarium has been well-established. We merely list some species in several categories that have been known to tolerate new-tank conditions.

Plecostomus

All species of Plecostomus species and their relatives (Loricariids) are Catfish. They should not be added to a new aquarium, as there will not be enough algae or plant matter for them to eat. For that matter, no algae-eating fish should be purchased until algae growth is sufficient. Diet of these fish must still be  supplemented with other foods. Channel catfish get huge.

Characins (Tetras and Relatives)

Black Neon Tetra

• Bleeding Heart Tetra (Hyphessobrycon erythrostigma)
• Red Minor Tetra (Hyphessobrycon serpae)
• Pristella (X-Ray) Tetra (Pristella maxillaris)
• Silver-tipped Tetra (Hasemania melanura)
• Black Tetra (Gymnocorymbus ternetzi)
• Diamond Tetra (Moenkhausia pittieri)
• Bloodfin Tetra (Aphyocharax rubripinnis)
• Lemon Tetra (Hyphessobrycon pulchripinnis)
• Black Neon Tetra (Hyphessobrycon herbertaxelrodi)
• Red Eye Tetra (Moenkhausia sanctaefilomenae)
• Buenos Aires Tetra (Hyphessobrycon caudovittatus)
• Congo Tetra (Phenacogrammus interruptus)
• Spotted Headstander (Chilodus punctatus)
• Striped Anastomus (Anostomous anostomous)
• Black-banded Leporinus (Leporinus fasciatus)

There are more than a thousand species of Tetras and other Characins. Most do not tolerate new-tank conditions, but we probably left out a hundred or so more that do. We have listed the hardiest of the most commonly-available species here. Cardinal, Emperor, Von Rio, Blue Emperor, Neon, Rummynose, Penguin and Glolite Tetras are commonly-found, and are very beautiful Tetras. However, none of those species will tolerate new tank conditions.

Thousands of these species are sold to unsuspecting new hobbyists by unknowledgeable employees at pet stores. They usually die rather quickly, giving the impression that all Tetras are hard to keep. Even these species are not hard to keep, provided they are introduced into a properly-aged, very peaceful community aquarium with other smaller fish.

Most Tetras are at their best in soft, slightly-acid water. Pacus are the largest of all the Characin species. They should not be purchased unless you have a very very large aquarium. Although Piranha are perceived as "tough" carnivores, they are not that tough when it comes to ammonia and nitrite. We do not recommend them to start a new tank. This is also true of the various Silver Dollar species. The Pacu is a very large Characin, related to the Piranha (but they're herbivores) that although very hardy, quickly grow gigantic, and will outgrow almost any aquarium, so we did not list them here.

Cichlids for starting aquariums

Tiger Oscar Cichlid

• Oscar (Astronotus ocellatus)
• Jack Dempsey (Cichlasoma octofasciatum)
• Convict Cichlid (Cichlasoma nigrofasciatum)
• Firemouth Cichlid (Cichlasoma meeki)
• Green Terror (Aequidens rivulatus)
• Jaguar Cichlid (Cichlasoma managuense)
• Festive Cichlid (Cichlasoma festivum)
• Midas Cichlid (Cichlasoma citrinellum)
• Pike Cichlid (Crenicichla lepidota)
• Peacock Bass (Cichla ocellaris)
• Port Cichlid (Aequidens portalegrensis)
• Rainbow Cichlid (Herotilapia multispinosa)
• Chocolate Cichlid (Cichlasoma coryphaenoides)
• Texas Cichlid (Cichlasoma cyanoguttatum)
• Wolf Cichlid (Cichlasoma dovii)
• Red Devil Cichlid (Cichlasoma festae)
• Severum (Gold and Green) (Cichlasoma severum)
• Salvini Cichlid (Cichlasoma salvini)
• Keyhole Cichlid (Cleithracara maronii)
• "Geophagus" jurupari (Satanoperca jurupari)
• Geophagus surinamensis (Geophagus surinamensis)
• Geophagus hondae (Geophagus hondae)
• Geophagus pelligrini (Geophagus pelligrini)
• All other Geophagus species (Geophagus sp. Satanoperca sp.)
• Blue Acara (Aequidens pulcher)
• Sheepshead (Flag) Acara (Aequidens curviceps)
• Jewel Cichlid (Hemichromis bimaculatus)
• Kribensis (Pelvicachromis pulcher)
• African Great Lake Cichlids (Malawi, Tanganyika, Victoria)
• All Tropheus species
• All Pseudotropheus species
• All Labeotropheus species
• All Melanochromis species
• All Julidochromis species
• All Haplochromis species
• All Tilapia species
• All Heterotilapia species
• All Cyphotilapia species
• All Lamprologus species
• All Neolamprologus species
• Almost All Other African Cichlids

We will not even attempt to list all of the Cichlids that can be used as starter fish for an aquarium, especially the many species of African Cichlids. Most Cichlids are very hardy fish and will cycle an aquarium with ease, but you may have noticed that we left off some very common Cichlids that do not make good fish for a new aquarium.

The most notable exceptions, the Angelfish (Pterophyllum sp.) and the Discus (Symphysodon sp.), which should NEVER be used to start a new aquarium. Many beginning hobbyists are not aware that the Angelfish and Discus are Cichlids, as both species are peaceful, and neither has the typical Cichlid oval shape. The Uaru (pronounced "waru"), is also a sensitive species.

It should be pointed out here that most species of Cichlids are aggressive fish, and many grow quite large. Most of the South and Central American Dwarf Cichlids are also too delicate to start a new aquarium. This includes nearly all of the Apistogramma species and the Rams (Microgeophagus sp.). The Red Parrot Cichlid, not listed here, is a "mule" hybrid between the Gold Severum and the Red Devil Cichlid. They have never survived a new tank when we've tried them.

Cyprininae (Barbs, "Sharks" and Relatives)

Tiger Barb

• Tiger Barb (Capoeta tetrazona)
• Sumatra (Green Tiger) Barb (Capoeta tetrazona)
• Clown Barb (Barbus everetti)
• Gold Barb (Barbus sachsi)
• Arulius Barb (Barbus arulius)
• Rosy Barb (Not long-finned) (Barbus conchonius)
• Black Ruby Barb (Barbus nigrofasciati)
• Checkered Barb (Barbus oligolepis)
• Spanner-T Barb (Barbus lateristriga)
• Red-tailed Shark (Labeo bicolor)
• Rainbow Shark (Labeo erythrurus)
• Black Shark (Morulius chrysophekadion)
• Apollo Shark (Luciosoma setigerum)
• Flying Fox (Epalzeorhynchus kallopterus)
• Siamese Flying Fox (Epalzeorhynchus siamensis)
• Chinese Algae Eater (Gyrinocheilus aymonieri)

With the exception of the Tinfoil Barb, we have not found a Barb yet that didn't make a good hardy fish for cycling aquariums. The one other exception is the Cherry Barb, which is not only one of the smallest Barbs, but in our experience, seems to be the most delicate of the commonly available species. Long-finned hybrids of some Barb species do not survive a new tank as well as the short-finned varieties. Ammonia can burn away the long flowing fins of these fish, and they may also be genetically weaker (due to in-breeding) than the original species.

Silver-scaled Barbs such as the Tinfoil Barb (and Bala "Sharks") are also not as hardy and tend to not tolerate ammonia nearly as well. The Chinese Algae Eater is not recommended, as they will feed on the slime coat of other fishes as well as algae when they get larger. Some literature has pointed this out, but has called this a mistake on the part of the fish, saying "they sometimes mistake the sides of large flat-bodied fish for smooth surfaces." This is not true at all. In our experience, and from other literature we've read, this is an intentional act, and adults of this fish have been known to prefer the slime coat of fish to algae.

Goldfish and Ornamental Carp

Black Moor Goldfish

• Comet (Carassius auratus)
• Shubunkin (Carassius auratus)
• Fantail (Carassius auratus)
• Black Moor (Carassius auratus)
• Koi (For ponds only) (Cyprinus carpio)

We listed the Goldfish and Carp separate from the other Cyprininae (Barbs, etc.), as they are temperate (cold water) species. Most of the expensive fancy hybrid goldfish do not make good starter fish. Their swim bladders are sensitive to injury, and genetic weakness due to in-breeding has made most varieties far more sensitive to their common Comet relatives. Fancy goldfish tanks are best cycled with Comets or White Cloud Minnows, which can then be removed when the tank is safe for the more-expensive fancy varieties. These include the Oranda, Ryukin, Pearlscale, Lionhead, Celestial, and Bubble-eye varieties.

Poeciliidae (Tropical Livebearing (viviparous) Fish)

Guppies

• Platies (Xiphophorus species)
• Guppies (Poecilia reticulata)
• Mollies (Poecilia species)
• Swordtails (Xiphophorus species)
• Variatus (Xiphophorus variatus)

These species are some of the best for beginning hobbyists, and are also the best for a beginning breeder. They are very hardy, are available everywhere and come in a wide variety of multi-colored hybrids. However, we have to caution that Fancy Guppies are not that ideal for starting a new tank. These beautiful hybrids will not usually tolerate ammonia well at all. If they live, their beautiful tails will get ragged, and may never grow back the same.

Melanotaeniidae (Freshwater Rainbowfish)

Melanotaenia Splendida

• Australian Rainbow (Melanotaenia fluviatilis (Also splendida))
• Red (New Guinea) Rainbow (Glossolepis incisus)
• Turquoise Rainbow (Melanotaenia lacustris)
• Boesemans Rainbow (Melanotaenia boesemani)
• Madagascar Rainbow (Bedotia geayi)
• Celebes Rainbow (Telmatherina ladigesi)

These are the most commonly-available Rainbowfish, at least in the Midwest. Almost all Rainbows are quite hardy, but of the species listed, the Madagascar and the Celebes are the most sensitive. Rainbowfish like clean water.

Rasborinae (Rasboras, Danios and Relatives)

Harlequin Rasbora

• Giant Danio (Danio aequipinnatus)
• Leopard Danio (Brachydanio frankei)
• Zebra Danio (Brachydanio rerio)
• Pearl Danio (Brachydanio albolineatus)
• Blue Danio (Brachydanio kerri)
• Harlequin (Common) Rasbora (Rasbora heteromorpha)
• Scissor-tailed Rasbora (Rasbora trilineata)
• Brilliant Rasbora (Rasbora einthoveni)
• Clown Rasbora (Rasbora kalachroma)
• Glowlight Rasbora (Rasbora pauciperfor)
• Giant Scissortail Rasbora (Rasbora caudimaculata)
• Fire Rasbora (Rasbora vaterifloris)
• Dwarf Rasbora (Rasbora maculata)
• Pearl Rasbora (Rasbora vaterifloris)
• Red-striped Rasbora (Rasbora pauciperforata)
• White Cloud Minnow (Tanichthys albonubes)

Caution! here, that we have had good luck with all of the species listed above. However, some hobbyists may have difficulty with some of the listed Rasboras. They do need a little more pampering in terms of small (5.0%) weekly water changes for the first couple of weeks. On the other hand, we have not yet encountered a Danio species that wasn't exceptionally hardy.