Okay, I was meaning to do this before and got lazy. I might as well do it now!
How to stock nano tanks:
Nano tank breakdown:
With space being limited nano aquariums are becoming more and more popular. With that though, people very easily overstock them. Now an overstocked tank isn’t necessarily the worst thing in the world, if you can manage it. You have options in almost every category too, so it’s very much possible. You can’t have every fish in the world though, so if the fish won’t be happy then simply don’t do it.
With all that said, what is a nano tank? For freshwater systems this is 2.5-20 gallons or about 10-80 liters. Now many keepers will give different numbers, but this is what I personally classify a nano or small aquarium to be.
Are they for beginners? No. I wouldn’t say most nano aquariums are for beginners. 40 gallons in my opinion is one of the best beginner sizes as it allows for the largest variety of fish and space for them. Why aren’t they good? Aren’t smaller tanks easier to maintain? In how many buckets of water you have to move, yes they are. Nanos are incredibly unstable though, and allow for less generosity missing a couple of weeks for a water change, overfeeding, or overstocking. They crash very easily. They also contain harder to keep fish with more particular needs in most cases. They also do far better when they’re natural as the plants will help keep balance.
I’m prepared for that. What can I keep and how do I choose?
As a disclaimer these are managed species only tanks. BIGGER is always BETTER. Don’t get a small tank if you’re serious about keeping these fish. Always go to the next tier if you can, your fish will thank you for it.
2.5 gallon:
Betta- Really the classic. Some wild betta are good too. But it’s the bare minimum for a single betta.
Bluefin Notho- You can do one in a 2.5 gallon. If you want more you’ll need at least a 10 gallon. Only one male per tank.
Inverts- You can get a large number of shrimp and snail species that would do wonderfully in a 2.5 gallon
I’m sure there are a few more but I don’t feel comfortable suggesting them.
5 gallon (Single species)
Red Flame Dario- You can have 1 male and 2 females. They require live foods and soft water. Make sure to have dense plants and for these guys small caves.
Asian stone catfish (Akysis)- It’s not known yet if these guys appreciate groups. 1 male and 1 female can be managed though. They will be shy, require sand and a small current. Nitrates must be kept below 5ppm.
Moth catfish (hara jerdoni)- They like small groups but only a pair is appropriate for a tank this size. You may be able to do 3 with caution. They’re very shy and great hiders. You need sand and driftwood.
Diptail Pencilfish- 3-5 can work. They’re shy and like still water. They require hiding spots. They scare very easily and are prone to jumping.
Chili rasbora- 6 needed and the max. They’re shy in smaller tanks. If in a bigger tank keep them with other nano fish under 2″. They require acidic water for long term health.
Least rasbora- Same as the chili. They’re even smaller though so really watch tank mates as bloodworms are larger than them. Also watch your filter, you don’t want them getting snatched.
Exclamation point rasbora- 6 max and min in a 5 gallon. Same as the two species above.
Emerald dwarf rasbora- Same numbers as the others. Not a picky fish but does best in a subtropical setting. Alkaline water. They go really well with dario in bigger tanks.
Celestial pearl danio/galaxy rasbora- 6/6 this is a theme, keep schools proper. Subtropical, neutral waters. DO NOT house with emerald dwarf rasbora! They breed with each other and the fry have a high mortality rate.
Gold ring danio- Hesitant to put them here, they’d do better in the 10+ gallon sections. They like subtropic waters. Bigger tanks are almost a must though as they require really large schools for long term success. 6 can be managed in a 5 gallon though…
Kubotai’s rasbora- Another one that I think is better in large tanks. But 6 can be managed in a heavily planted 5 gallon. They look so much better in big schools in big tanks.
Asian rummynose- Alkaline water, subtropical setting. 6 can be managed though they’re active and would appreciate more space.
Neon blue rasbora- Acidic water is a must. Nothing above 6.5 and can get as low as 4. small tolerated temp window too of 74-78′f. Consider a larger tank for these beauties as they shine in schools of 20+
Gem minnow (Tanichthys micagemmae)- They’re like mini white clouds and require very similar care. they do best in stream tanks.
Lyretail killifish- Should be in a species only. You want only 3 in a 5.5 but can add another per 2 gallons after. The males fight but it’s often not deadly.Subtropical conditions.
Clown killifish- Jumpers and species only. They like acidic water. Twhy will breed in a healthy mature tank. two males to four females is a good ratio. They thrive on live foods.
Florida flag fish- More of a cichlid than a killi. One male with 2-3 females. they’re territorial so be prepared to separate if there’s fighting. They do well with other higher subtropical native fish.
Norman’s lampeye- These guys look cool! They’re very subtle and adaptive. Keep in a group of 6 and just make sure the temperature stays in a 74-78 range as temperature is their biggest stressers.
Hovering zebra loach- These guys will make use of every inch of the tank they’re offered. So if you can give them more please do so! 6 to a 5 gallon they’re very active and fun fish. Have a small current, an airstone and keep in a subtropic setting. They feed best on micro foods.
Rosy loach- Similar to the zebra loach except less outgoing. Have them in a group of 8 at least and make sure parameters are good. The males have a stunning red colour.
Licorice gourami- Beautiful delicate fish. You can keep a small group in a 5 gallon. They’re hard to feed and require very soft and acidic water to thrive. They’re relatively new so research is still being done.
Samurai chocolate gourami- A hardy and beautiful fish. One can go in a 5 gallon or a pair in a 10. They’re a challenge to find but not hard to keep or breed. They need acidic water and a biotope is best for them.
10 gallon:
All the above can be housed in a 10 gallon happily. In some cases you can mix 2 species of choice. Species only are often the most stable.
Honey gourami (Colisa chuna)- Sweethearts. 1 in a 10 gallon and 3 (1m:2f) in a 15. They go really well with cories and pencil fish. Do not house with betta or other gourami species.
Ocellated Shell-dweller and Banded shell-dwellers (multis) - Lake tanganyika conditions. They require soft sand and many large shells that they can hide in. Does best as a species only. 1m:3f
Pea puffer- So much personality. Must be kept in a species only. They like hard water. Must have snails in diet as well as meaty live and frozen foods.You should have a really good culture of ramshorn or pond snails going.
Sparkling gourami- More bold if kept alone they require micro foods. not hard to care for but prefer acidic or tannins in the water. 1m:3f though they’re very hard to sex. Males won’t fight .
Peacock gudgeon/goby- One of my all time favorite fish. A male and female pair does great in a 10 gallon. Keep away from timid fish or anything with long fins as they will nip. Males fight with each other for territory and it can get rough so 1 male per 20 gallons.
Scarlet goby- Expensive and tricky to care for. They have small ranges for parameters and will often only feed on live foods. High oxygen water is a must. If that doesn’t deter you they will do great in a species only tank with plenty of rocks. 1 male to 1 female.
Stiphoden gobies- There are a number of species but they all fall into similar care. The tank must be established with natural algae and micro fauna. They do extremely poorly on a protein rich diet and dry foods. Gel foods that are high in plant matter may be used. Cooler subtropical water is often preferred as well as a current, oxygen and stable water. They will hide if no fish are in the upper tank portion.
Scarlet Badis- Little fish with a lot of rage. 1 male and 3 females can be kept in a planted 10 gallon. Generally undemanding though they like hard water and are hard feeders. If you don’t have ones already transferred to dry you’ll have to feed mostly live and frozen. They are not aggressive feeders.
Rice fish- Relatively new to the hobby they’re small fish with a guppy like personality. They breed readily but a small group will do just fine in a 10 gallon. They can be paired with betta if kept at the high temperature range. Some betta will fight them though.
Neon dwarf Rainbowfish- It’s a mini version of your larger rainbowfish. They like hard water and are easier to keep than the blue eyes. try to get an evenly sexed school of 6.
Forktail blue-eye- Beautiful bright fish. They require a planted tank and are easy to feed. They like a bit of flow and high oxygen. 6-8 in a tank.
Spotted blue-eye rainbowfish and paskai- I’m putting these together as they’re pretty identical in care. They do better in bigger tanks but can do alright in a 10. Get captive bred ones as wild are fragile. The more acidic the water the happier they are but can tolerate hard water.
Ornate bushfish- African gourami is the best way to describ them. Hard acidic water and strictly tropical waters. They do best in a Congo biotope. They don’t take flakes well.
Dwarf gourami - I like thee guys in bigger tanks but can be kept in a 10 alone. Care is much like a betta.
Albater cory, tailspot,salt and pepper and pygmy - All have close requirements. 75′f is best, they like a current, soft sand, lots of hiding and a fish to swim overhead. They do better on a protein based diet than an algae diet. Very active. They swim in the low to mid range. 6-8 in a 10.
Clown panaque - It’s one of the best plecos for a small tank. MUST have driftwood, more types the better. Fresh veggies can supplement. These are not algae eaters.
Pygmy and Marbled hatchet - Only real difference is the size. Pygmies can be kept in a group of 10 and Marbles 6-8. Make sure to have floating plants and a secure lid. They will jump. Even doing water changes they will jump. Hard acidic water is preferred.
White cloud minnow- They’re active and will appreciate more space but are fine in a 10. They do best in cold water or low subtropic. They’re long lived and breed easily. Extremely adaptive. A school of 6-8.
Coral red Pencilfish- New fish in the hobby. They have adapted to captive life beautifully. Have a lot of floating plants. They eat well . Males may fight so more females is better. 6-8 fish. Soft acidic water with little current.
Dwarf pencilfish- A classic nano fish. Keep in a group of 6-10, Neutral soft water is favored. Must have a planted tank as they have a unique social system and fights for dominance are common. More females than males.
Zebra Danio- Classic hardy fish. PH and hardness are unimportant but they do like subtropic waters. One of the perfect captive fish. Keep in a group of 6.
Dadio (Laubuca dadiburjori)- New fish in the hobby but appearing more as they’re easy to breed, Soft acidic water. Tropical temps. They take prepared foods really well. Make sure they have a lid as like most hatchet like fish they will jump.
Cherry barb- Great beginner fish! Undemanding in all parameters, just avoid extreme heat and cold. Keep in a group of 6-8. They aren’t as flighty as other barbs.
Guppies and endlers (As well as most other central america live barrers)- They can go in a 10. I don’t think they should but they can. Try to keep all females as males will fight and mixing will breed. Keeping this section brief.
Skipping 15 gallon as it’s not a typical tank. The most common varity is a taller 10 gallon s consider stocking options to be the same with more water quality room.
20 gallon:
Bristlenose pleco- Popular and widely available. Must have wood in their diet but these guys will graze on algae.
Reticulated Driftwood Cat- Nocturnal catfish with beautiful coloration. Feeds mostly on worms and does poorly on shrimp. Likes a take with a lot of driftwood and a strong directional current. Choose tank mates wisely.
Cories - All other medium bodied cories. Not super demanding, likes a current and cooler water. Remember they are omnivores and need meat as well as veggies. 6-8 can be kept in a 20 long comfortably.
tetra (small to medium bodied) - I’m lumping them together as they all require the same tank size. Please look up your species of choice.
Blotched pyrrhulina - Surface fish and perfect tankmates for Apistogramma. They will not eat fry. Hard to feed though as they will only take micro foods despite their 2″ size. Hard to find but if you do 6-10 will do fine. Make sure to have surface cover and a lid.
Apistogramma (Agassiz,borelli, and Cockatoo)- They look different but are simular. A pair would be happy in a 20 gallon, Make sure to have driftwood, rocks, flowerpots and anything else for cover.
Checkerboard cichlid -Blackwarter tropical setting. They should be the only cichlid in the tank. A pair goes well with some tetra. Microfeeder so you’ll need small frozen or live foods.
Masked Jukidochromis - Tanganyika conditions. A pair would be more than happy. Provide rock piles that they can safely use as caves. High protein diet. Excellent parents.
Flag cichlid - Like most keep in a pair. They’re a little hard to sex but there are tricks. These guys are territorial when spawning but generally okay in a small community setting.
Rams - Classic dwarf cichlid. They’re sensitive and more picky with partners. Make sure you have a mated pair or they will fight relentlessly. Soft warm waters is a must. Great fish overall. Watch for breeding aggression.
Kribensis- A large number of colors are available. Males are bigger than females and they’re territorial so put with fish that can take a beating. Stack wood and have plenty of plants. They do best on a live diet but will take dry.
kuhli loach- Highly adaptable but like soft acidic water most. Make sure to have soft sand with these guys if possible. Cute little wiggle worms. keep in proper schools the more the better!
Okay my brain is mush now. There are more species for 20 gallons but this is a good start for most. I did not suggest goldfish because they really do better in bigger and at that point it’s no longer a nano in my eyes. Same as dwarf snakehead and axolotl. Those are specialty tanks and not really nice community tanks. Add more if you wish. Do you water testing and changes. Learn how to grow plants and enjoy your nanos. I’m open to questions on combinations or additional species. Remember less is best but keep proper pairs and schools.
