Can I mix different corydoras species in the same tank?

Yes — different species cohabit peacefully in most cases. But there's a subtlety: for proper schooling behaviour, each species needs its own subgroup of 6+. A tank of 3 panda cories + 3 bronze cories = two stressed subgroups. A tank of 6 pandas + 6 bronzes = two functioning schools. Either go single-species with 6+ or mixed-species with 6+ of each.

What's the best substrate for corydoras?

Soft sand, ideally fine-grade. Alternatives: smooth rounded aquarium gravel (no sharp edges). Avoid: sharp-edged crushed gravel, coarse quartz, substrate with particle size over 3 mm. Sharp substrate damages corydoras' sensory barbels — the whisker-like appendages they use to find food. Damaged barbels lead to chronic infections and slow starvation [5].

Do corydoras eat other fish food or need special food?

They eat what sinks. Standard tropical flake food that sinks before being eaten by water-column fish is fine for corydoras. Dedicated sinking catfish pellets (Hikari Sinking Wafers, Fluval Bug Bites Catfish) are the target supplementary feed — drop 2–3 pellets per 6-cory group at lights-out, 3–4 times per week.

Are corydoras hardy enough for a new tank?

Not in the first 4–6 weeks of a new tank. Corydoras are moderately sensitive to ammonia spikes — more than Bronze cories specifically — and a new tank with unstable parameters kills them. Wait until the tank has been cycled 6+ weeks with stable zero ammonia/nitrite before adding corydoras.

Can corydoras live with shrimp?

Yes, completely safe. Corydoras are gentle substrate foragers; adult shrimp ignore them, shrimplets may occasionally be nibbled but mostly coexist. A planted 90 L with 6 corydoras + 10 cherry shrimp is one of the most peaceful substrate combos in the UK hobby.

Why do my corydoras swim to the surface constantly?

Corydoras are facultative air-breathers — they swim to the surface occasionally to gulp atmospheric air. Once or twice per hour is normal. Constant surface breathing means low dissolved oxygen in the tank (over-stocked, under-filtered, temperature too high) — add an airstone, check temperature, and review stocking levels [3].

Do corydoras need a heater?

Most species yes. Bronze (C. aeneus) and peppered (C. paleatus) tolerate room-temperature UK tanks at 18–22 °C — they're the cool-tolerant exception. Panda (C. panda), habrosus, pygmaeus, and most tropical corydoras want 22–26 °C and need a heater in a standard UK home.

Can male and female corydoras be distinguished?

In mature adults yes. Females are slightly larger, broader-bodied, and deeper in profile (when carrying eggs very obviously so). Males are slimmer and slightly more pointed. The reliable sex indicator appears during breeding behaviour — males chase females in T-position (male perpendicular to female). Outside breeding, juveniles are impossible to sex.

Do corydoras breed in home aquariums?

Yes, most species do readily once mature (8–12 months). A cool water change (water 3–4 °C below tank temp) triggers spawning — females deposit eggs on tank glass or plant leaves in tight groups held between pelvic fins. Fry hatch at 4–6 days and eat crushed flake food immediately. Panda cory is the most commonly-bred UK species; bronze is second.

How long do corydoras live?

5–10 years, species-dependent [1]. Bronze corydoras reliably hit 7–8 years in well-maintained tanks. Panda cory averages 5–6 years. Smaller species (pygmy, habrosus) 3–5 years. The substrate-welfare factor matters here — corydoras in harsh-substrate tanks with damaged barbels live half as long as those in sand substrate.

Where should I buy corydoras in the UK?

Whichever retailer you pick, check three things before buying: (1) is the shop-tank substrate sand or smooth rounded gravel (not sharp crushed quartz)? If the cories you're about to buy have been sitting on sharp substrate, their barbels are already damaged [5]; (2) are there 6+ corydoras of the same species in the shop tank? Solo cories are stressed cories; (3) can the staff tell you the scientific name? 'Bronze cory' is Corydoras aeneus — a seller who doesn't know that is a seller who's casual about the welfare basics. For rare species (CW-numbered wild-caught, laser cory CW010), budget £15–£50 and expect specialist-only availability.

What are the most popular cory catfish types?

The cory catfish (sometimes spelled 'cory dora') you'll meet most often in the UK trade are, roughly in order of popularity: the bronze cory (Corydoras aeneus) and its albino form, the peppered cory (C. paleatus), the warm-water sterbai cory (C. sterbai), the panda cory (C. panda), the tiny pygmy cory (C. pygmaeus), and the julii/leopard cory (C. julii / trilineatus) [1]. They're all kept the same way — 6+ of one species, smooth substrate, sinking food — but they differ in adult size and temperature: bronze and peppered tolerate cool unheated tanks, while sterbai and panda want it warmer. We have dedicated guides for the [bronze](/bronze-corydoras-uk), [albino](/albino-corydoras-uk), [julii](/julii-corydoras-uk), [panda](/panda-corydoras-uk) and [pygmy](/pygmy-corydoras-uk) cories if you want to compare them in detail.

Catfish & Plecos · Buying Guide

Corydoras UK: The Substrate Community Fish Every Tank Should Have

Read or listen to our UK Corydoras guide - smooth substrate, group size, species choice, feeding, tank mates and welfare-first buying tips.

Shop Catfish & Plecos in stock →

By Tom WhitfieldUpdated 18 April 202611 min read

A Salt and Pepper Catfish (Corydoras habrosus) on soft substrate — Product photo · Tropical Fish Co warehouse· Own

Listen to this guide · 5 min0:00 / 4:54

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Bronze Corydoras (Corydoras aeneus) peaceful community catfish

−10%

Easy

Bronze Corydoras (Corydoras aeneus)

22–26°C · pH 6–7.5 · 60L

£2.69£2.99

Easy

Pigmy Corydoras (Corydoras pygmaeus)

22–26°C · pH 6–7.5 · 30L

£4.99

Easy

Bronze catfish (Corydoras aeneus long fin)

22–26°C · pH 6–7.5 · 60L

£4.99

Albino Golden Cory (Albino Corydoras) real fish side view - SKU 8184

Easy

Albino Golden Cory (Corydoras aeneus)

22–26°C · pH 6–7.5 · 60L

£2.99

Easy

Panda Cory Catfish (Corydoras panda)

20–25°C · pH 6–7.5 · 60L

From £8.69Some sizes on sale

Easy

Peppered Corydoras (Corydoras paleatus)

18–25°C · pH 6–7.5 · 60L

£4.99

Easy

Elegant Cory (Corydoras elegans)

22–26°C · pH 6–7.5 · 60L

£7.99

Mini Cory / Light-Spot Catfish (Gastrodermus nanus) exact source and aquarium views

−15%

Moderate

Mini Cory / Light-Spot Catfish (Gastrodermus nanus)

22–26°C · pH 6–7.5 · 60L

£5.94£6.99

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Ideal water conditions at a glance

The shaded band shows the range corydoras is comfortable in. Match it to your tap water before you buy.

Temperature22–26 °C

18 °C32 °C

pH6–7.5

Hardness2–15 dGH

0 dGH30 dGH

early:

Symptom	Likely cause	Action
Gasping at surface	Low O₂ or gill issue	Add airstone, check stocking
Barbels short/missing	Substrate damage	Change to sand immediately
White cotton-like patches	Fungal infection (from abrasion)	Antifungal + substrate fix
Erratic darting	Nitrite spike	Test water, 50% change
Bloating + sitting still	Internal parasite	Quarantine + metronidazole
Red streaks on fins	Ammonia burn	Test water, full change if needed
Pale colour + listless	Chronic stress	Check group size + substrate

Most corydoras deaths in UK tanks come from (1) undersized groups → chronic stress → immune suppression, or (2) sharp substrate → barbel damage → secondary infection. Fix both before reaching for medications [5].

Our welfare-first live-fish shipping

Corydoras are moderate shippers — hardier than tetras because of body size, but sensitive to dissolved oxygen loss during transit.

APHA-compliant live-animal carrier (a licensed live-animal courier)
Oxygen-charged double bags with extra headspace for multi-cory groups
Insulated polystyrene with temperature-matched packs
Minimum 7-day species-isolated quarantine before shipping
Drip-acclimation protocol included with every shipment

The welfare rule we follow in-shop: never ship fewer than 3 corydoras together. Solo cories arrive stressed and often don't recover. Our minimum order unit for corydoras is 3, and we recommend 6 minimum for the welfare reasons above.

UK corydoras community

British Cichlid Association — has a Corydoras interest section
Planet Catfish — international species ID database with UK-active forum ^[6]
Facebook "UK Catfish Keepers" — breeder swaps + species ID
FBAS — regional clubs with catfish breeders
Practical Fishkeeping — regular corydoras features

Ready for more?

Our corydoras care guide covers species-by-species care, breeding setups, and disease diagnosis for the genus.

Compatible species: the cardinal tetra buying guide covers the water-column companion; the best beginner tropical fish list positions cories alongside other community essentials.

Full range: catfish & plecos hub and the bottom dwellers hub cover every substrate-dwelling species in stock.

Related categories

Visual route into the rest of our UK live-fish range.

Catfish & Plecos

Aquarium catfish and plecos for sale UK — Corydoras, Bristlenose, L-number rare plecos, Synodontis, Farlowella, Otocinclus.

Bottom Dwellers

Bottom dweller fish for sale UK — Corydoras, Loaches, Plecos, Synodontis. Cleanup crew for the aquarium substrate.

Community Tank Fish

Community tank fish for sale UK — peaceful, compatible species that coexist happily. Perfect for mixed-species tropical aquariums.

Frequently asked questions

Six minimum, eight to ten ideal [2]. This isn't folk wisdom — peer-reviewed research on C. aeneus schooling behaviour shows measurable stress-cortisol elevation in groups below six, with feeding behaviour suppression and shortened lifespan [2]. Six is the welfare floor. Above ten, more is fine, though practical tank size limits how many you can keep.

Sources & further reading

Every claim in this article is backed by a source below. We group them by type so you can judge the weight of each one at a glance.

Peer-reviewed study (1)

[2]
Kohda, M. and T. Hori (2000). Schooling behaviour in Corydoras aeneus. Environmental Biology of Fishes, 57. View source
Peer-reviewed study confirming minimum-group-size welfare requirement.

Scientific database (1)

[1]
Froese, R. and D. Pauly (Eds.) (2024). Corydoras aeneus — Bronze Corydoras. FishBase. View source
Source for bronze corydoras parameters and distribution.

Conservation authority (1)

[4]
(2023). Corydoras genus — IUCN assessments. IUCN. View source
Conservation status by species; some wild-collected species are data-deficient.

Hobbyist reference (3)

[3]
(2024). Corydoras genus — Seriously Fish. Seriously Fish. View source
Species-by-species husbandry reference.
[5]
Nathan Hill (2023). Corydoras care in the UK aquarium. Practical Fishkeeping. View source
UK husbandry + substrate-welfare reference.
[6]
(2024). Corydoras — Planet Catfish genus profile. Planet Catfish. View source
Species identification + CW-number reference for rarer lines.

Expert video (1)

[8]
Cory McElroy (2023). Corydoras catfish care — group size and substrate. Aquarium Co-Op (YouTube). View source
Observational reference for substrate + feeding behaviour.

Government / regulatory (1)

[7]
(2024). Aquatic animal welfare — substrate requirements. RSPCA. View source
UK welfare guidance on substrate appropriateness for bottom-dwellers.

Spotted something that needs a fix?

Fishkeeping moves fast and we want every guide spot-on. If you think something here is wrong, out of date, or could be clearer, tell us — our team reads every message and updates the page.

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Corydoras UK: The Substrate Community Fish Every Tank Should Have