Pimelodidae (Long-whiskered Catfishes)

Ornate Pimelodus

Pimelodus ornatus

The Ornate Pimelodus, also known as the Ornate Catfish (scientific name Pimelodus ornatus), belongs to the family Pimelodidae. This species is one of the most picturesque representatives of catfish, distinguished by its peaceful nature and ease of care, provided that the aquarium is properly equipped and fitted with a powerful filtration system. However, due to its maximum size and the need for a significant tank volume (aquarium, filters), this catfish may require substantial financial investment.

Tank
from 540 L (143 gal)
Temperature
22 – 26 °C (72 – 79 °F)
Size in aquarium
28 cm (11 in)
Acidity
pH 6–7.2

Dangerous to small fish

Natural rangeRange on the map
  • South America area
  • Argentina
  • Brazil
  • Colombia
  • Ecuador
  • French Guiana
  • Guyana
  • Paraguay
  • Peru
  • Suriname
  • Venezuela

Tank conditions

Plan the tank stocking
Temperature
22 – 26 °C (72 – 79 °F)
Water pH
Slightly acidic (6) – Neutral (7.2)
Water dH
Very soft (2) – Very hard (18)
Water salinity
no salt (freshwater)
Size in aquarium
28 cm (11 in)
Lifespan
8 years
Temperament
Semi-peaceful dangerous to smaller ones
Toward small fish
a risk to small fish
Required aquarium volume
from 540 L (143 gal)
Lighting
dimmed
Substrate
sandy (regular, light)
Water flow
moderate or strong
Feeding
Any (universal)
Keeping
Small group 3–4 individuals
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (small group (3–4 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adults of this species can reach a length of up to 28 cm. Their distinctive feature is a pattern of alternating light silvery and dark stripes, which continue onto the caudal fin. Their fins are transparent, and a large black spot is noticeable on the dorsal fin. Around the mouth are three pairs of barbels, one of which is very long, comparable in length to the fish's body. The barbels serve the catfish for orientation in space and for finding food.

Habitat

This species is widely distributed throughout the entire Amazon River basin; it can be found in almost all countries of South America. These fish inhabit small bodies of water, including small rivers, tributaries of large rivers, and temporary lakes formed in coastal areas during the rainy season.

Behavior and Compatibility

This species has a peaceful and friendly disposition towards its conspecifics and other fish of similar size and temperament. However, for small fish, it poses a direct threat: due to its indiscriminate eating habits, they can become an accidental victim of the Ornate Pimelodus. It is recommended to keep them in small groups.

Care and Maintenance

For keeping one adult specimen, an aquarium of at least 540 liters will be required. The same volume will also be suitable for a small group of young Pimelodus. When setting up the aquarium, ensure ample swimming space, create subdued lighting, and provide several appropriately sized shelters. Plants are not an essential decorative element, but if you plan to include them, choose undemanding species such as Anubias, ferns, and mosses. It is important to note that lighting directly affects the behavior of these catfish: under moderate, dim light, they actively move around the aquarium, whereas under bright lighting, they prefer to spend most of their time in shelters, only emerging at night. The performance of the filtration system is of particular importance. The fish produce a lot of waste and require high water quality, so, in addition to filtration, it is necessary to clean the substrate weekly and perform partial water changes (15–20% of the total volume) with fresh water.

Diet

This is a carnivorous species; in its natural habitat, its diet consists of small benthic invertebrates, and occasionally small fish. In aquarium conditions, catfish can be fed live, fresh, or frozen foods such as tubifex, bloodworms, earthworms, as well as chopped mollusks and freshwater shrimp. Popular dry sinking foods are also acceptable: flakes, granules, or pellets. It is important to avoid overfeeding, as the Ornate Pimelodus can eat until its belly is excessively distended, which can lead to digestive problems. Meaty foods are recommended to be offered once every few days, and dry food in small portions daily.

Breeding and Reproduction

In their natural habitat, these catfish spawn during the rainy season, and the breeding period is preceded by an upstream migration, which is extremely difficult to replicate in a home aquarium. For commercial sale, this species is primarily bred on specialized fish farms, and much less frequently, especially for the European and Asian markets, it is caught from the wild.

Diseases

The main reason for health problems in these fish is an unsuitable environment. At the first signs of illness, it is essential to immediately check water parameters and ensure there are no high concentrations of dangerous substances (such as ammonia, nitrites, nitrates, etc.). Once the parameters are normalized, treatment can begin. The Ornate Pimelodus has no scales, and its skin is very delicate, making it extremely sensitive to many common medications. Before using any medication, carefully read the instructions, and if in doubt, it is recommended to halve the dose.

How to choose

When choosing an Ornate Pimelodus, carefully inspect its skin: there should be no white film, ulcers, or signs of damage on the body, as this species is prone to skin diseases. A healthy specimen will have intact fins, without signs of splitting, and its behavior in the store will be active but cautious, with a clear interest in the substrate. Avoid purchasing fish with sunken bellies or unnaturally bloated abdomens, which may indicate problems with internal organs or parasites. — avoid individuals that constantly lie on their side or make chaotic movements — check the integrity of the barbels, as damage to them hinders orientation and food search — keep in mind that the fish has sharp pectoral spines, so use thick bags for transport and be careful when transferring to avoid injury.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Ornate Pimelodus get?

An adult reaches 28 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Ornate Pimelodus need?

The recommended volume is 540 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Ornate Pimelodus need?

Temperature 22–26 °C, pH 6–7.2, hardness 2–18 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Ornate Pimelodus live?

Around 8 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Ornate Pimelodus aggressive?

Temperament: semi-peaceful (dangerous to smaller ones). Not a predatory species, but small fish that fit in its mouth will eventually be eaten.

How many Ornate Pimelodus should be kept together?

Recommended setup: small group (3–4 individuals). Ignoring this is a common cause of stress and disease.

What does Ornate Pimelodus eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Ornate Pimelodus?

The scientific name of the species is Pimelodus ornatus, family Pimelodidae (Long-whiskered Catfishes). It also appears in the literature as: Megalonema rhabdostigma.

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Other scientific names and conservation status

Other scientific names
Megalonema rhabdostigma
Categories
Catfish
Conservation status
Least concernLC