Snoring Catfish (Wertheimeria maculata)

Choose a rare Brazilian thorny catfish

The Snoring Catfish (Wertheimeria maculata) is a large, rarely seen catfish from eastern Brazil, and the only member of its genus. "Snoring Catfish" is the common name used for it on Planet Catfish, and the Danish name listed there, gulplettet tornmalle, translates as "yellow-spotted thorny catfish", a good description of an adult. The species name maculata means spotted.

It belongs to the thorny catfishes, the family Doradidae, which also includes the talking and Raphael catfishes sold in UK shops. A 2014 study of the group's relationships by Birindelli placed Wertheimeria with Kalyptodoras in a new subfamily, Wertheimerinae, as the sister group of all the other thorny catfishes. Unlike most of its relatives, it lacks the hooked thorns on the bony plates along the side.

We have found no published study of the sounds this species makes, so treat "snoring" as a trade name rather than a promise of a particular noise.

Decide from the complete care picture

Very little has been published about keeping it. As the Scotcat species page puts it, not a lot is known about the husbandry of this large thorny catfish, so this page sets out what the sources do say and where they disagree.

Know what you are buying

One purchase supplies one live Snoring Catfish. It is sold in one standard size with no size grade, and it is not an adult, so plan the aquarium for the full adult size below. No reliable external sex differences have been published, so sex is not specified. Read our delivery information for dispatch days and arrival terms before you order.

Young and adult fish look very different. Vono and Birindelli's 2007 study of its natural history, summarised by Scotcat, describes a reddish to olive ground colour, with large whitish vermiculations (worm-like markings) on small fish and sparse dots on larger ones. Scotcat also notes only about three bony plates (scutes) on the front of the body, with the rest of the lateral line a soft, unossified tube.

Check your fish against these points

Our photographs show the species, not the individual you will receive, and a young fish will not match an adult picture.

Plan the aquarium around a 30 cm catfish

Planet Catfish and FishBase both give a maximum of 300 mm standard length (measured without the tail). The Suedamerikafans catfish database gives about 35 cm total length, with 220 mm standard length documented, and recommends a tank 180 cm long. No source we found gives a minimum width, so choose a tank deep enough from front to back for a 30 cm fish to turn easily among caves and wood.

Our tank volume calculator converts your tank's dimensions into litres, and our stocking calculator helps you check the total load with every other fish at adult size.

Use a three-step space check

1. Measure the length: about 180 cm or more.
2. Plan the floor: space for at least one large cave or root tangle the catfish can fit inside as an adult.
3. Add the companions: include every other large fish at adult size, not the size you buy it at.

Recreate a deep river pool

The species is found only in the Jequitinhonha river basin of Minas Gerais and the Pardo river of Bahia, both draining to the Atlantic coast of eastern Brazil. Vono and Birindelli caught it mostly in the rainy season, only in the main channel and the larger tributaries, in deep pools at running or backwater sites; artisanal traps made of bamboo and lianas worked best.

For the aquarium, OATA's catfish guidance recommends sand or fine gravel to protect the barbels, and caves, wood, pots or plants as cover. A deep-pool layout puts those together:

Divide the footprint by function

Fix heavy rocks firmly on the glass base, not on top of the sand, so a large catfish digging underneath cannot topple them.

Set water values within the published range

Aim for the species figures: 22–26°C and pH 6.5–7.2. No hardness range has been published for this fish, so keep it moderate and, above all, stable. UK tap water ranges from soft to very hard depending on the region, and hard water usually runs at a higher pH, so test yours before you buy. Our water matcher compares your water with each fish's needs, and our water chemistry guide explains pH and hardness.

Separate habitat values from waste readings

Temperature and pH describe the habitat; ammonia, nitrite and nitrate measure waste. OATA's targets of zero ammonia, zero nitrite and nitrate no more than 20 mg per litre above tap water apply whatever the habitat values, and they matter more with a large fish eating fruit and meaty foods.

Filter and heat for a large fish

OATA says a filter is always essential for catfish and recommends a 25% partial water change every week, siphoning solid waste from the substrate, with replacement water treated to remove chlorine or chloramine. It also says a heater is needed to keep the temperature stable all year. Our filtration guide explains how to size a filter for a large tank, and our article on the nitrogen cycle explains why the tank must be mature first.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite, nitrate, pH and temperature.
2. Siphon the sand around the cave and under the wood, where food collects.
3. Change at least 25% of the water with conditioned water at tank temperature.
4. Remove any fruit or vegetable left from the last feed.
5. Rinse filter media in removed tank water, never under the tap, when flow drops.

Feed fruit and insects as well as sinking foods

In the wild, Vono and Birindelli found a varied diet made up mainly of food falling into the river from the bank: chiefly fruits and land insects from the riverside vegetation. The Suedamerikafans database also lists plant food. In the aquarium, that points to a mixed diet rather than one type of pellet.

OATA recommends appropriate sinking foods for catfish, fed once a day, giving only what is eaten within a few minutes, or up to 30 minutes for slow grazers, because uneaten food breaks down and fouls the water.

Build one measured meal

1. Staple: large sinking catfish pellets or wafers, placed near its cave.
2. Fruit: on some days, small pieces of soft fruit in place of part of the staple.
3. Insect foods: insect-based pellets or thawed frozen foods for variety.
4. Timing: if the fish hides through the day, feed shortly after the lights go out and check the next morning that nothing is left.

Introduce it gently and handle it with care

OATA advises that catfish travel double-bagged and that the tank must show zero ammonia and nitrite before any fish goes in. Use the floating-bag method: switch off the lights, float the sealed bag for about 10 minutes, add small amounts of tank water over up to 20 minutes, then release the fish while keeping the bag water out. Lift a catfish in a container rather than a net where you can, because fin spines catch in netting. Our acclimatisation guide covers each step.

Use a first-week checkpoint plan

Choose tank mates too big to swallow

No source we found describes this species' behaviour with other fish. The safe general rule for any 30 cm catfish is to keep it only with fish too large to fit in its mouth, in a tank with enough caves that no two large bottom-dwellers have to share one.

Use the same five questions every time

1. Do the water ranges overlap? Check every companion against 22–26°C and pH 6.5–7.2.
2. Is every fish too big to swallow? Assume an adult can take any fish that fits in its mouth.
3. Is there a cave for each bottom-dweller? Add one before adding another catfish.
4. Does each schooling species get its full group? Count complete groups.
5. Can every fish feed? Sinking food must reach the catfish before mid-water fish take it.

Our tank mates tool checks a planned mix for you. If you like thorny catfishes but have a smaller tank, compare our Hancock's Talking Catfish, Painted Talking Catfish and Spotted Raphael Talking Catfish, or browse the South American Catfish category, our catfish and plecos, our bottom dwellers and our rare and collector fish.

Watch health and behaviour

OATA lists the signs of a healthy catfish as clear, bright eyes, undamaged fins, intact scales or skin, no ulcers or bumps, normal swimming and steady breathing. Warning signs include clamped fins, flicking against objects, white spots or fluffy growths, erratic swimming, a change in colour, faster or slower gill movement and a reduced appetite.

Pair each observation with an action

Understand breeding and conservation

The sources disagree on breeding. Planet Catfish states that no member of the genus has been bred in the aquarium. Scotcat reports successful breeding in Brazil by an exporter, and the Suedamerikafans database records breeding at a Brazilian fish farm, citing a 2019 article by Hans-Georg Evers. From wild fish, Vono and Birindelli suggested partial spawning, because they caught some fish in advanced maturity and others fully spawned at different times.

The IUCN assessed the species as Least Concern in 2018. Scotcat notes threats within its small range from siltation, habitat fragmentation, pollution and introduced species.

Answer Snoring Catfish buying questions

What is a Snoring Catfish?

It is Wertheimeria maculata, a large thorny catfish (Doradidae) found only in the Jequitinhonha and Pardo river basins of eastern Brazil. "Snoring Catfish" is the common name Planet Catfish uses for it.

Why is it called the Snoring Catfish?

It is a trade name. We have found no published study of the sounds this species makes, so do not buy it expecting a particular noise.

How big does it grow?

Planet Catfish and FishBase give 30 cm standard length; a German catfish database gives about 35 cm total length.

What size tank does it need?

A tank around 180 cm long or more, as recommended by the Suedamerikafans database, with a large cave or root tangle.

What water conditions does it need?

22–26°C and pH 6.5–7.2 (Scotcat), with zero ammonia and nitrite. No hardness range has been published, so keep it stable.

What does it eat?

In the wild mainly fruits and land insects. In the aquarium, give sinking catfish foods with pieces of fruit and insect-based foods.

Which fish can live with it?

Large, peaceful fish too big to swallow, such as silver dollars, provided their water needs overlap. Its behaviour with other fish has not been documented.

Has it been bred?

Sources disagree: Planet Catfish says the genus has not been bred in aquariums, while Scotcat and the Suedamerikafans database report breeding in Brazil.

Why does my young fish look different from an adult?

Small fish have large whitish worm-like markings; larger fish turn reddish to olive with sparse spots.

Consult the care references

• Planet Catfish: Wertheimeria maculata: common names, maximum size, distribution, IUCN status and breeding note.
• FishBase: Wertheimeria maculata: classification, maximum length, habitat type and distribution.
• Scotcat: Wertheimeria maculata: habitat, diet, colour, scutes, spawning and conservation from Vono & Birindelli (2007, Ichthyological Exploration of Freshwaters 18(2): 183–191), plus temperature and pH.
• Suedamerikafans catfish database: Wertheimeria maculata: sizes, recommended tank length and Brazilian breeding report.
• Birindelli (2014), Phylogenetic relationships of the South American Doradoidea, Neotropical Ichthyology 12(3): subfamily Wertheimerinae.
• OATA: How to look after catfish: water quality targets, maintenance, substrate, feeding, transport and acclimatisation.