I’ll be honest. I never liked owning corydoras.
But I say that so when I say, “Owning pygmy cories is amazing!” you’ll believe me. Seriously though, my pygmy tank has been my favorite tank of all time.
Not only are they so much cuter than they look in the pictures. And, let’s be honest, they already look pretty adorable.
But they’re also active, entertaining, easy to care for, and a breeze to breed. It’s impossible not to love these guys!
The pygmy cory (corydoras pygmaeus) is the smallest of all the corydoras species. Possibly the smallest catfish in the world.
It’s cousins, Corydoras hastatus and habrosus are also mistakenly called a pygmy cory.
Neither of them are pygmy cories. Though they are both smaller cory species. These cousins are more appropriately called dwarf cories.
So with that in mind, this article is only going to cover pygmy corydoras, not all three species.
Disclosure: we’re reader-supported! So if you buy a product I recommend, I might make some coffee money at no cost to you.
Table Of Contents
What do pygmy cories eat?
They’ll gladly accept any food that fits in their mouth.
But it’s important to feed them a rounded diet that includes meat, veg, and algae. I cover options in more detail in the feeding section.
How many dwarf corydoras are in a school?
Corydoras don’t school, they shoal.
Schooling fish swim together in a highly coordinated way. Think minnows and sardines.
Shoaling fish are fish that swim together in groups when threatened. But they still go off and do their own thing when they feel safe.
At any rate, six is the minimum I’d recommend. In the wild, they shoal in groups numbering in the thousands. The more you can get, the more natural and fun their behavior will be.
Will pygmy cories eat shrimp?
Pygmy cories devour baby brine shrimp. But they won’t touch your cherry or crystal reds.
I’ve never heard of them eating shrimplets unless they’re dead or insanely slow.
These guys aren’t hunters, so they’re not going to be super active to get their food. As long as it moves out of the way, it’ll be safe.
Distribution & Natural Habitat
Pygmy cories are endemic to Rio Madeira basin in Brazil. They’re usually seen along the banks or in surrounding flooded forest areas.
They enjoy hiding among tree roots and marginal vegetation in small tributaries, creeks, and pools that flow out from the basin.
The Maderia river is a sediment-rich white water river. Though it’s dark, it’s not blackwater.
Pygmies do best in lower light situations since they’re not exposed to a ton of light in the wild.
Size: 1.3″ (3.5 cm) max
Lifespan: 4 years, maybe longer?
Tank Size: 10 gallons (40 liters)
Diet: Omnivore – opportunistic
Temperature: 60– 78F (15 – 25C)
There are some big things – size aside – that set the pygmy apart from other cory cats. First off, they do a lot of swimming.
Most cories can be seen rooting around the bottom of the tank, but these guys go everywhere. And they do swim instead of scoot about on the bottom.
They’re also awesome at playing dead. It doesn’t seem to be intentional. They just rest… oddly. For extended periods of time.
The third – and my personal favorite – is that they don’t eat eggs or fry. So you can leave them all in the same tank to be one big, happy, colony!
I do wish they’d eat the infertile eggs though.
A 10-gallon is the minimum I’d suggest. Though a 20-gallon long would be much better for them.
These are one of the few catfish that do use vertical and open space for swimming. So you’ll want to make sure you have plenty of swimming space for them.
And you definitely want a tight-fitting lid. Preferably with some air space between the lid and the water.
These guys will shoot up to the surface periodically to gulp air. And when they do they can launch themselves like tiny torpedoes.
So unless you want to want to come home to an empty tank….
You’re gonna want a lid.
One of the great things about the pygmy cory is that you can keep them at room temperature. As long as your house is comfortably warm, that is.
In fact, I would recommend you don’t get a heater unless you’re worried about drafts in the winter.
If you do opt for heater, make sure you grab one that’s adjustable. The programmed ones will get too hot for them.
They have a light bioload and they are incredibly social. And it’s unbelievably sweet to see them all huddled up together resting!
It’d be hard to overstock these guys if you have a proper cycle, so load them up!
However, structure and swimming space are important. So it’d be wise to give them lots of nooks and crannies to explore as your numbers go up.
Plus entertaining for you!
Again, six is the absolute minimum I would do. And, honestly, you’re doing yourself an injustice by only having six.
They are so much more fun to watch in large groups and their behavior is more natural.
Every pygmy gets up to their own antics and they’re a never-ending delight to watch when you have a dozen or more. A dozen might sound like a lot of fish, but they’re like $2 per fish.
So buy them up and make the cost of shipping worth it! It’s worth not buying coffee for a week, isn’t it? (It is!)
In the wild, pygmy corydoras are found along the banks weaving in and out of root structures, marginal vegetation, and flooded forests.
They love tangled up roots, thick plants, leaf litter, seed pods, and all sorts of other fun things to explore.
For replicating roots, I find that spider wood works well. Plus it gives you plenty of opportunities to cut, chop, and glue it however you like.
If you’re an avid reader, you’ve definitely heard me mention Tannin Aquatics’ Sterculia Pods. Which has been a huge hit with my cory colony.
I always see at least eight in or huddled on top of it. Munching away, cuddling, resting. You know, catfish things.
Tannin also makes some awesome curated packs. One of my favorites for these guys is this Jau River pack from South America. It has all sorts of awesome flooded jungle vibes.
Again, I’m not affiliated with Tannin in any way, I just adore them endlessly.
Another big thing to note is that pygmy corydoras have barbels that can get damaged by sharp substrate or bacteria. For that reason I don’t suggest bare bottom.
HTH pool filter sand is great and I’ve never had an issue with it being too sharp or holding too much bacteria. Their barbels are as long and adorable as ever!
Plus HTH super cheap.
But I recommend you buy it in person because it’s not worth the shipping. But if you want to plant high-maintenance plants, sand isn’t going to cut it.
With these guys, it’s best to avoid substrates that are fine or powdery. They’ll just make a mess of it.
I included the best substrates below if that sounds like your situation.
Best Plants For Pygmy Cory
Pygmy cories do better with some plants. Carpeting plants are ones that I would avoid.
Carpeting plants require a ton of overhead light – which your pygmy cory won’t love. And they don’t let your pygmy cory root around in the sand like they naturally would.
If you’re looking to get the most natural and rewarding behavior, I suggest low light plants that can be grown in sand. And I happen to have a handy list of just those.
Because I got your back. Obviously.
Java moss is an almost bulletproof plant that requires almost no care. It doesn’t grow nearly as slowly as it’s java fern cousin, and can create lush moss beds that blow and billow in the current. They’re a great option for grazers, fry, or those of you with the blackest of thumbs.
Java fern is a nearly indestructible low light plant that can put up with tons of abuse. It doesn’t need Co2, fertilizers, or fancy soils. There are tons of lush, beautiful, jungle-like aquascapes you can create with it too!
Water wisteria is a fast-growing plant good for keeping ammonia, nitrates, and nitrites under control. It’s great for providing shelter for scared fish and fry, keeping cyanobacteria (aka blue-green algae) at bay, and has anti-microbial properties.
Salvinia is a fast-growing plant good for keeping ammonia, nitrates, and nitrites under control. It’s great for providing shelter for scared fish and fry, keeping the lighting intensity down. and making skittish fish feel more secure.
Lighting & Filtration
These guys don’t do great with bright lights or high flow. They do, however, need good water circulation.
I find that a couple of air stones places around the tank on full blast mixed with a well-cycled sponge filter give them the optimal level of circulation without having to battle a raging current.
These little ones aren’t strong enough to put up with a torrent of water for long. But they do seem to enjoy playing in the bubbles from time to time.
I would be wary of canister filters, HOBs, or box filters because of the fry.
I’m sure the adults could handle it with some fine-tuning, but chances are pretty good you’ll end up with fry at some point if you have six of these little loves.
As far as lighting goes, they are much more at ease when their lighting is subdued. You can accomplish this through and adjustable light, tannins, or floating plants.
When they have bright lights on them, they tend to shoal up. Which is, again, a sign of stress and not a behavior you want to see all the time.
If you want suggestions on lights, filters, or air pumps, I’ve included my favorites below for you.
Provided your tank is properly cycled, you can get away with relatively few water changes with these guys.
They’re not tolerant of ammonia, nitrites, or nitrates, but I’ve never had a problem with their bioload – despite feeding them tons of live foods.
Ideally, you want to change 10% of their water weekly. But you could definitely get away with changing 25% monthly.
If you add tannins to the water, I would lean closer towards the monthly schedule than the weekly one.
They don’t do super well when you change their water chemistry frequently, and changing their water weekly would likely send the pH all over the place. Of course, this is my experience with it.
Just something to think about and be aware of so you can work out what’s best for your particular situation.
The biggest concern with cories is the bacteria levels in the substrate. Be diligent about cleaning up leftovers, otherwise you may start to see barbel infections.
If you don’t know what to get for water care or meds, I’ve included a handy shopping list below.
Feeding pygmies is a delight. They enjoy food – can’t say I blame them! – and are generally unpicky little creatures.
This makes them fantastic tank inhabitants!
But that doesn’t mean you should feed them just any food. In the wild, their diet would consist largely of microfoods. This would be tiny organisms that live in biofilm.
Foods like brine shrimp, vinegar eels, microworms, white worms, grindal worms, and daphnia are all readily eaten by them as well.
If you’re not into live food, I’ve also fed them freeze dried tubifex, freeze dried blackworms, frozen bloodworms, freeze dried or frozen mysis, golden pearls, and decapped brine shrimp eggs.
It is important to include some veggie foods in their diet. They are omnivores – though they do lean towards carnivore more.
Algae wafers are prepared foods like Repashy Soilent Green are great options for including greens.
On the topic of Repashy’s food, they also devour Spawn & Grow as well as Grub Pie. The only food I haven’t had success with are pellets. Even after they become soft and powdery, they’re not interested in eating it.
Still, these guys are the least picky fish I’ve ever owned.
For the whole list of foods and where to find it, I included a handy shopping cheat sheet below. 3 – 4 is probably sufficient for these guys, but more is always better.
Pygmy Cory Diseases
Here’s where pygmy cories lose a few points.
Most of them are wild caught, so it’s not their fault. If you happen to find captive-bred pygmies, you probably won’t run into as many issues.
But if you’re buying them, be aware that quite a few nasties can pop up over the course of the first few months and it’s super important to put them through a proper quarantine period.
Although it’s more common in cold-water fish, any fish can get it so long as the temperature range is low enough. It’s a parasite that, unlike ich, is difficult to detect in the beginning stages. Once in it’s advanced stages (which make takes months to present themselves) you’ll likely be able to detect it but, at this point, you have to respond quickly as it’s already been taking a toll for quite some time.
- Grey or white patches on the skin
- Ichthyobodo (protozoan parasite.)
Bacterial infection is a broad term, the bacteria family can cause a wide range of symptoms and come from varying causes. Generally, you can treat them with a broad spectrum antibacterial regardless of the particular bacteria at hand. It’s diagnosing that’s usually the hard part.
Making matters even more difficult, fish can have an internal or external bacterial infection.
- Red streaks
- Red ulcers
- Fuzzy growths
- Pop eye
- Poor water quality
- Food that’s gone bad
- Keeping fish in inappropriate water parameters
Tapeworms are small rice-like worms that can drop out of your fish’s anus with or without passing poop with it. Due to the small size of the segments these worms break into, it can be incredibly hard to diagnose in fish.
- Sunken stomach
- Inability to grow
- Generally not thriving
- Infected by another fish
Skin & Gill Flukes
Skin and gill flukes are worm-like parasites that embed into your fish. Since they’re so small, they’re almost invisible to the naked eye and incredibly difficult to diagnose.
Before you freak out, flukes are present in almost every tank and are harmless under normal conditions.
- Excess mucus on skin
- Redness in gills and on skin
- Labored breathing (if in gills)
- Generally, stress
- Previous illness
- Wrong water parameters
Fungal infections are a tricky bunch – not only do they have a huge family that presents a wide variety of species and symptoms – but some bacterial infections look strikingly similar to a fungus.
If you’re not sure if you’re dealing with a fungus or a bacterial infection, I find it helpful to treat with Ich X and Erythromycin (provided it’s 100% erythromycin) at the same time to be sure I’m treating for both.
- Cottony growths on body, fins, eyes, and/or gills
- Prior untreated injury
- Water quality-related issues
- Prior untreated infection (bacterial, parasitic, etc.)
Pygmy Cory Tank Mates
If these pygmies were larger, they’d make an ideal community fish. Unfortunately, due to their size, they can be harassed, intimidated, or even eaten by larger tank mates.
If you want to go for a community tank, you should look for peaceful additions that are roughly the same size.
A common suggestion is shrimp like cherries.
I would avoid these guys just because they both reside primarily at the bottom and one will almost always disturb the other. If you want to try it, there aren’t going to be territory wars. Just make sure no one is constantly disturbed or looks stressed out.
Your best bet would be adding boatloads of structure for them to perch on, hide under, and cling to. Guppy grass, driftwood, seed pods, leaf litter, and other structures will be your best friend.
This strategy should help minimize overlapping rest areas (like the bottom) where they’re highly likely to disturb each other.
Onto what I actually suggest.
I was so excited about putting this list together! I got to include so many squee-worthy fish and fish that I don’t get to include often. This isn’t a complete list, but I hope it inspires you to look into some other awesome and unusual choices for your aquarium.
Let’s get to some minis!
Toucan Tetras (Tucanoichthys tucano)
These guys are hard to find (but I know a few good spots if you want them!) And they’re completely worth hunting down these rare gems. They’re a peaceful shoaling fish that need to be kept in groups of six or more and the only known wild population exists within a 200-meter range in Brazil.
pH: 4.0 – 6.5
dKH: 1 – 8
Temp: 68 – 83F (20 – 28C)
Size: 1″ (2 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top
Chili Rasboras (Boraras brigittae)
Chilis are tiny. Absolutely minuscule compared to your average aquarium fish. They’re also shoaling fish that need to be kept in groups of at least 10 – but, again – they’re tiny! Even still, they pack a colorful punch once settled in and make a beautiful, active display for the right tank.
pH: 4.0 – 7.0
dKH: 1 – 10
Temp: 68 – 83F (20 – 28C)
Size: .5″ (1 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top
Emerald Dwarf Rasboras (Microrasbora erythromicron)
A beautiful shoaling species that needs to be kept in groups of six or more. Even still, they can be a little timid without the right plant coverage. Once settled, they’re an active, gregarious, and beautiful addition to the right aquarium!
pH: 7.0 – 8.0
dKH: 12 – 20
Temp: 68 – 76F (20 – 24C)
Size: .75″ (1 cm)
Temperament: Shy shoaling fish
Swimming: Mid to top
White Clouds (Tanichthys albonubes)
These fish are best kept in groups of eight or more, though 10 is better. There’s little information of just how far spread these fish are, but they’ve been observed slow-moving white and blackwater streams in and around China.
pH: 6.0 – 7.0
dKH: 5 – 20
Temp: 60 – 72F (15 – 22C)
Size: 1.5 – 2″ (3 – 5 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top
Lambchop Rasbora (Trigonostigma espei)
You can think of the lambchop as a smaller cousin to the harlequin rasbora (Trigonostigma heteromorpha) they look and act similarly and their care requirements are about the same. These guys are just a bit smaller with slightly different coloring.
pH: 5.5 – 7.5
dKH: 1 – 10
Temp: 74 – 83F (24 – 28C)
Size: 1.2″ (1 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top
Ember Tetra (Hyphessobrycon amandae)
Ember tetras are bright, fun, tiny, shoaling fish that occur in South American black waters. They’re hardy, peaceful fish that are often described as active, bold, and playful. They also enjoy a planted tank, but be mindful that they do like to swim in open space, so be sure to include that in your layout. They enjoy their numbers a little higher than most shoaling species, 8 is recommended.
pH: 5.5 – 7
dKH: 1 – 10
Temp: 68 – 82 F (20 – 27 C)
Size: 3/4″ (2 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Sparkling gourami (Trichopsis pumila)
Little known fact about sparkling gouramis; they’re quite social and gregarious creatures! Although they don’t school or shoal, they do enjoy social interactions with their own kind – in fact, most gourami do! – and we suggest a four minimum to make sure they’re comfortable.
pH: 6 – 8
dKH: 5 – 18
Temp: 72 – 81 F (22 – 27 C)
Size: 1.5″ (4 cm)
Temperament: Peaceful, can be aggressive when spawning
Swimming: All water
Celestial Pearl Danio (Danio margaritatus)
CPDs or Galaxy Rasbora (although they’re not a rasbora or a danio,) are small shoaling species. When stocking, buy as many as possible, 8 being the minimum I’d personally suggest. There have been reports that they’re hard to transition onto prepared foods, but this may be wild-caught specimens. There are numerous reports that they’ll take finely crushed flakes and micropellets.
pH: 6.5 – 7.5
dKH: 5 – 15
Temp: 69 – 79 F (20 – 26 C)
Size: under 1″ (2.5 cm)
Temperament: Peaceful, can be shy
Swimming: Mid-water shoaling
Pencilfish (Nannostomus sp.)
Pencilfish is a genus containing 19 currently recognized species. Some popular options are diptails, Beckford’s, and coral. Although it’s a large genus, the care is similar for all of them and you should aim for a shoal of at least six.
Research into a specific species and their requirements is strongly recommended.
pH: 5.0 – 7.0
dKH: 4 – 12
Temp: 74 – 82F (23 – 27C)
Size: 2″ (5 cm) species dependent
Swimming: Mid to top
Breeding Pygmy Cory
Breeding pygmy corydoras is a snap. As long as you take care of them like I’ve outlined already, they’ll breed for you just fine. Of course, I’m not going to leave it there.
I’ll break everything down for you, but just know it doesn’t require any extra effort on your part in most cases.
To start, you’ll need more 1 female for every 1 – 2 males, though 2 is suggested. I know this sounds counter intuitive but, trust me, I’ve tried to not do it this way and failed horribly.
You can tell the difference between a male and female based on their size and shape. Females are larger and rounder. They look very femininly curvy, if you will.
Males are smaller and sleeker. Large males usually have a flat forehead that slopes down sharply to their mouth. Females tend to have more rounded heads.
You’ll need to feed them lots of high-quality foods to get them into spawning condition. The females will begin to look noticeably larger and plumper.
Once you see this, you’ll know they’re almost ready – or are ready – to breed.
If they seem on the verge of spawning but aren’t thoroughly convinced yet, try a large 50% water change. Some people say cooler water than what’s in your aquarium, some people say with warmer…
I’ve found that either works.
What seems to be most important is that the temperature is different.
Once they start breeding, one male will chase a female who is ready to lay eggs. This usually prompts competition from another male (or even more then one) and they’ll all follow the female.
She’ll eventually pick a spot and a male and they’ll form a T-position. The male kinda looks like he’s sitting on her nose. She’ll carry a tiny egg between her pelvic fins and deposit it somewhere.
It’s tough to explain in words, so here’s a video for you.
Skip ahead to the 9-minute mark to see some breeding activity, or you can watch him walk through his whole breeding setup. If they’re in a species only tank, you won’t need another tank. They don’t predate on their fry or eggs.
From there, it’ll be left alone and it’ll hatch anywhere from 3 – 5 days.
Egg & Fry Care
Once the fry hatch, they are almost invisible little black dots. They’ll absorb their yolk sak for anywhere between 2 – 4 days.
Once they use up the nutrients in their yolk sak, they’ll start swimming around hunting for the tiniest food you can possibly imagine. If your tank was set up properly and fully mature, they should have no issue finding food.
If it wasn’t, you’ll want to start an infusoria culture before you embark on this process.
It’ll take them anywhere from 3 – 6 months to be fully grown and start spawning themselves. Around the one month mark, they’ll be able to eat whatever food you feed their parents.
I’ve found pygmy corydoras spawn almost constantly once they start as long as they’re happy and well fed.
The cycle seems to last about a week, at which point I do a 10% water change and they’re back at it. No one seems to be entirely sure just how many eggs they can lay, but I’ve counted 75 between three breeding females over the course of a week.
And that’s only counting the eggs I watched them lay.
Some sources suggest one female can lay as many as 50 eggs over the course of a week, but there doesn’t seem to be any official numbers.
Telling The Difference Between Dwarf Cory Species
Corydoras pygmaeus and Corydoras hastatus are the two that seem to gather the most confusion – likely due to their similarly tiny stature.
Pygmaeus has a black line that runs horizontally from their barbels to the caudal peduncle (the start of their tail.) Corydoras hastatus, on the other hand, has no line.
They have a little black diamond on their caudal peduncle and have shimmery green see-through skin.
Habrosus I’m, honestly, not sure how it gets confused.
Habrosus also has a black line, but their line isn’t straight and looks splotchy. The majority of their pattern is spotted or speckled. Pygmaeus has no speckling or spotting and their black line is almost pin-straight.
I’m researching a chinese moutain stream biotope which is why I was looking at pygmy cories. Do you think theyd do ok with hillstream loaches and roseline sharks?
If you’re going for a Chinese mountain stream biotope, none of those species would fit because none of them live there. The only commonly available species – that I’m aware of – would be white clouds. But if you feel like doing some digging, there are tons of other fish that live in those habitats. Depending on which river you’re looking at and if you want to be super accurate about it, you might be able to find a rare species or two to toss in.
The fish fauna of mountain streams in the Guanshan National Nature Reserve, Jiangxi, China and The fish community of a high mountain stream in Taiwan and its relation to dam design are good places to start looking. With that said, I’d still encourage you to take a little creative liberty with the word “biotope” if that sounds like too much work. Starting a biotope without getting totally overwhelmed is really the hardest part.
Maybe no biotope then it looks like allot. would they do ok in a tank together?
Hmmm. It’s possible, but I’m inclined to say no on the pygmy cories. Pygmies don’t do well with fast-moving, food-aggressive, or large fish (and roselines are all of those!) and they don’t do great with fast water – which both species need. Though some other cory species might work alright if you dial the water movement down to moderate and add some airstones to make up for the oxygen.
I think hillstreams would be compatible enough with roselines. You’d just want to make sure the more food-aggressive roselines don’t gobble up all the hillstream food. And, of course, both species need at least 6 of their own kind, and roselines need a pretty big tank.
I did not relize how much space roseline sharks needed! I think Ill stick with the pygmies. thanks for the help!!!
Any time, glad I could help!