Two-Spot Catfish (Mystus nigriceps)

Choose Mystus nigriceps for a large catfish aquarium

Mystus nigriceps, the Two-Spot Catfish, is a bagrid catfish (family Bagridae) from South-East Asia. It has a long, slender body, a long, low adipose fin on the back and the long barbels that give the genus its name: FishBase explains that Mystus comes from the Greek mystax, meaning whiskered. Published sizes differ. Wikipedia, citing an earlier FishBase version, gives 19.8 cm, while FishBase and ScotCat now give a maximum of 30 cm total length (TL, including the tail). ScotCat warns that Mystus nigriceps will prove predatory in the aquarium, so it is a fish for a large tank with robust companions.

The species name nigriceps means black head (ScotCat). It was described by Valenciennes in 1840 as Bagrus nigriceps; Bagrus micracanthus, described by Bleeker in 1846, is a junior synonym, and older books may call it Mystus micracanthus. Wikipedia records that the fish was sold in aquarium circles without a scientific name until it was matched to Bleeker's description. The common name has its own history: an early artist's impression showed no obvious markings, but a researcher in the early 1940s described two body spots, which is where the name Two-Spot (FishBase: Twospot catfish) comes from.

Sources disagree about its range. ScotCat restricts it to Java and southern Sumatra in Indonesia, with Java as the type locality. FishBase lists the Mekong basin, Malaysia and Indonesia, and Wikipedia gives Cambodia, Indonesia, Laos, Malaysia, Singapore and Thailand. FishBase and ScotCat agree on the habitat: lowland streams and peat waters, with adults living in large rivers. FishBase lists it as Least Concern on the IUCN Red List (assessed 2019), and ScotCat notes that it is common where it occurs in Java.

Recognise Mystus nigriceps

Markings vary between fish and change with age and mood, so look at the body shape and the long adipose fin as well as the spots. Browse our other Mystus catfish, the Asian catfish section, or the wider other catfish category.

Compare it with the Mystus we already sell

We stock several catfish from the same genus, and they are not interchangeable. The closest in name is our Mystus Catfish (Mystus sp.), an undescribed form whose adult size is unverified; its page expects it to stay below about 15 cm. M. nigriceps is a described species that FishBase and ScotCat record to 30 cm TL, so it needs a larger aquarium and bigger companions.

Check the name before you compare care

Our Pyjama Catfish (Mystus vittatus), Long Whiskered Catfish (Mystus gulio) and Albino Yellow Mystus Catfish are other members of the genus. Read each page for its own size and care rather than assuming they match this one.

Know exactly what you receive

• One live Mystus nigriceps per purchase, supplied as a young fish in the standard size available. It is not yet fully grown.
• Sex is not selected. No sexing information is published for this species; in the similar-sized Mystus singaringan, Seriously Fish notes that males have quite a long genital papilla just in front of the anal fin, a feature that only shows in mature fish.
• Our photographs are illustrations. Markings vary between fish, as the published descriptions above show.

Decide between one fish and several

No source describes how M. nigriceps behaves towards its own kind. For Mystus singaringan, a species of similar maximum size, Seriously Fish says it is usually intolerant of its own kind and advises keeping only one unless the aquarium is very large. Until better information exists, plan on one fish per aquarium, or a very large tank with a separate shelter for each fish if you want more. Read our delivery and Live Arrival Guarantee terms before you order.

Plan a 120 × 45 cm aquarium as the minimum

No care sheet gives a tank size for this species. Seriously Fish's profile of Mystus singaringan, which reaches 300 mm standard length, sets a minimum base of 120 × 45 cm, about 243 litres, and we use that as the floor here. Because M. nigriceps can reach 30 cm TL, extra length and width are always better. OATA's guidance on large fish adds a planning rule: choose a tank that can house the fish at full size from the start, because many large species grow quickly.

Our tank volume calculator turns your measurements into litres, so you can compare your tank with the 243-litre guide figure.

Use a three-step space check

1. Measure the base: confirm at least 120 × 45 cm.
2. Count the bottom-dwellers: allow one territorial Mystus per tank and no other territorial bottom-dwelling catfish.
3. Plan for an adult body: use 20–30 cm, whatever size you receive.

Build a dim, sandy layout with shelters

Seriously Fish says décor is not critical for M. singaringan but that it needs hiding places, such as driftwood shelters, flowerpots or lengths of PVC pipe, and ideally a soft, sandy substrate. It also notes that the fish is seen more often when floating plants cut the light reaching the bottom. OATA recommends sand or fine gravel for all catfish because of their sensitive barbels, with cover from plants, wood, pots or caves. That suits the lowland streams, peat waters and large rivers where M. nigriceps lives (FishBase).

Divide the footprint by function

If you keep more than one bottom-dwelling fish, give each its own shelter at opposite ends of the tank so they do not compete for the same cave.

Match the water values

Three sources give values for this fish or a close relative, and they overlap well. FishBase gives 20–26°C, pH 6.0–7.0 and 5–19 dH. ScotCat gives 22–27°C and pH 6.0–7.0. Seriously Fish gives 22–27°C, pH 5.6–7.0 and 1–12 dGH for M. singaringan. The aim column is the range where they agree.

Tap water in many parts of the UK is hard, with a pH above 7, so test yours before you buy. Stable values matter more than chasing an exact figure, so avoid repeated chemical adjustments, and treat every water change with a conditioner that removes chlorine and chloramine. Our water matcher compares your readings with the ranges above, and our water chemistry guide explains pH and hardness.

Separate habitat values from waste readings

These limits come from OATA's catfish guidance. A large predatory catfish produces a lot of waste, so test weekly and after every new addition.

Filter strongly and keep a weekly routine

For an aquarium of about 243 litres, Seriously Fish suggests a filter rated at 970–1,215 litres per hour, four to five turnovers of the tank volume every hour, and a heater of about 175–275 W in a room at around 20°C. Keep the filter mature by cleaning it gently and never all at once. Our guide to aquarium filtration explains the choices.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite, nitrate, pH and hardness at least once a week.
2. Change about 25% of the water at least once a week, as OATA recommends.
3. Treat the new water with tap-water conditioner and bring it to tank temperature.
4. Siphon waste from the sand, working round the shelters.
5. Rinse filter media only in the old tank water, never under the tap.
6. Check that the catfish comes out to feed and shows no damage to its barbels.

Feed a varied, meaty diet

In the wild M. nigriceps eats insect larvae and zooplankton (FishBase). In aquariums it takes most prepared foods (Wikipedia, citing Planet Catfish), and Seriously Fish calls the similar M. singaringan an unfussy feeder that accepts most small live, frozen and dried foods, and advises keeping the diet varied. OATA recommends sinking foods for catfish, fed once a day in amounts eaten within a few minutes.

From our range, Welsi Gran sinking catfish granules make a good daily base, with frozen red mosquito larvae and frozen Mysis through the week.

Build one measured meal

• Use sinking food: granules, pellets or thawed frozen food that reaches the bottom quickly.
• Feed near its shelter: the catfish can eat without crossing a brightly lit open floor.
• Watch for a few minutes: check that it eats and that faster tank mates do not take everything.
• Remove leftovers: siphon out anything still uneaten after a few minutes.
• Vary the menu: alternate dry food with frozen foods through the week.

Introduce it to a mature aquarium

Before the fish arrives, make sure ammonia and nitrite read zero and that the temperature and pH sit within the ranges above. Use OATA's floating-bag method: switch off the aquarium lights, float the sealed bag for 10 minutes to equalise the temperature, add small amounts of tank water over up to 20 minutes, then release the fish, leaving as much bag water behind as possible. Our guide to acclimatising new fish walks through each step.

Catfish carry spines on their pectoral fins and just behind the gills, so OATA advises handling them with care and double-bagging them for transport. Spines catch easily in a net; lifting the fish in a container is gentler for both of you.

Use a first-week checkpoint plan

Expect the catfish to hide for the first days. A fish that never comes out to feed, breathes rapidly or shows damaged fins needs attention.

Choose robust tank mates

ScotCat warns that M. nigriceps will prove predatory in the aquarium, and Wikipedia notes that it is not safe with smaller fish because it will eat them. For the similar M. singaringan, Seriously Fish describes a somewhat robust species that can be territorial and aggressive depending on the individual, says it should not share a tank with other territorial bottom-dwellers, and suggests larger barbs such as tinfoil or lemon-finned barbs, Apollo sharks and large cichlids as companions.

From our range, the Tinfoil Barb and the Albino Tinfoil Barb match that advice. Check each pairing in our tank mates tool, and browse our catfish and plecos if you are planning a larger mixed tank.

Screen every companion the same way

Read its normal behaviour

FishBase notes that the genus Mystus breathes air facultatively: as well as using their gills, the fish can take air at the surface. FishBase also describes M. nigriceps as demersal, living near the bottom, so expect a fish that spends much of its time on or near the floor and in its shelter, coming out more under floating plants and in dimmer light.

Pair each behaviour with a response

Handle the spines and watch its health

OATA lists the warning signs that something is wrong in a catfish aquarium. Check them at every feed, and when you see one, test the water before doing anything else.

Pair each sign with an action

OATA adds a rule for every aquarium fish: never release an unwanted fish or plant into the wild. If the catfish outgrows your tank, ask a fish shop or club to rehome it.

Know the breeding notes

FishBase records that M. nigriceps lays eggs and that its pairing behaviour is possibly like that of other bagrid catfish, but it gives no details, and we found no report of aquarium breeding. Seriously Fish says the related M. singaringan is not thought to have been bred in aquariums either.

Answer Mystus nigriceps buying questions

What is Mystus nigriceps?

Mystus nigriceps, the Two-Spot Catfish, is a bagrid catfish from South-East Asia with a long, slender body, a long adipose fin and long barbels. It lives in lowland streams, peat waters and large rivers, eats smaller fish in the aquarium and needs a large tank with robust tank mates.

Why is it called the Two-Spot Catfish?

An early illustration of the species showed no obvious markings, but a researcher in the early 1940s described it with two body spots, and the common name comes from that description. FishBase lists it as the Twospot catfish. The Latin name nigriceps means black head.

How big does Mystus nigriceps get?

Published sizes differ. Wikipedia, citing an earlier FishBase version, gives 19.8 cm, while FishBase and ScotCat now give a maximum of 30 cm total length. Plan the aquarium for a catfish of up to 30 cm.

Is it the same fish as your Mystus Catfish (Mystus sp.)?

No. Our Mystus Catfish (Mystus sp.) is an undescribed form whose adult size is unverified and probably under 15 cm. Mystus nigriceps is a described species recorded to 30 cm, so it needs a bigger aquarium and bigger tank mates.

Will Mystus nigriceps eat small fish?

Yes. ScotCat warns that it will prove predatory in the aquarium, and Wikipedia notes that it is not safe with smaller fish because it will eat them. Keep it only with fish too large to swallow.

Can I keep more than one Mystus nigriceps?

Its behaviour towards its own kind is not documented. Seriously Fish says the similar-sized Mystus singaringan is usually intolerant of its own kind and advises keeping one unless the aquarium is very large, so plan on one fish per tank.

What size tank does Mystus nigriceps need?

No species sheet gives a figure. Seriously Fish sets a minimum base of 120 × 45 cm, about 243 litres, for the similar-sized Mystus singaringan, and that is the floor we recommend. A larger tank is better for a fish that can reach 30 cm.

What water does Mystus nigriceps need?

FishBase gives 20–26°C, pH 6.0–7.0 and 5–19 dH, and ScotCat gives 22–27°C and pH 6.0–7.0. Aim for 22–26°C and pH 6.0–7.0, with zero ammonia and nitrite and nitrate no more than 20 mg/l above your tap water.

What should I feed Mystus nigriceps?

In the wild it eats insect larvae and zooplankton. In the aquarium it takes most prepared foods: feed sinking granules or pellets with frozen bloodworm and Mysis, once a day and only what it eats within a few minutes.

Consult the care references

• FishBase: Mystus nigriceps (Twospot catfish) — maximum size, water values, distribution, habitat, wild diet, air-breathing in the genus, identification features and IUCN status.
• ScotCat: Mystus nigriceps — synonyms, name meaning, distribution, size, temperature and pH, the two-spot description and its warning that the species is predatory in the aquarium.
• Wikipedia: Mystus nigriceps — synonyms, naming history in the aquarium trade, size, distribution and the warning about smaller tank mates (citing FishBase and Planet Catfish).
• Seriously Fish: Mystus singaringan — genus-level guidance from a similar-sized Mystus: tank size, layout, water values, filtration, diet, behaviour, tank mates and sexing.
• OATA: How to look after catfish — UK guidance on catfish waste limits, substrate, maintenance, feeding, acclimatisation, handling and health signs.
• OATA: How to look after very large (tankbuster) fish — planning for adult size, lids for large fish and never releasing fish.
• Tropical Fish Co delivery policy — current dispatch and Live Arrival Guarantee terms.