Armored Catfishes (Loricariidae)

Spiny Pleco

Pseudacanthicus spinosus

Pseudacanthicus spinosus, known in the aquarium hobby as the Spiny Pleco or Ornate Pleco, is a species of catfish from the family Loricariidae, also referred to as Armored Catfish. This inhabitant of South American waters is widely distributed throughout the vast Amazon River basin.

Tank
from 250 L (66 gal)
Temperature
23 – 28 °C (73 – 82 °F)
Size in aquarium
26 cm (10 in)
Acidity
pH 5.8–7.5
Natural rangeRange on the map
  • Brazil

Tank conditions

Plan the tank stocking
Temperature
23 – 28 °C (73 – 82 °F)
Water pH
Slightly acidic (5.8) – Neutral (7.5)
Water dH
Very soft (2) – Very hard (18)
Water salinity
no salt (freshwater)
Size in aquarium
26 cm (10 in)
Lifespan
12 years
Temperament
Territorial often aggressive
Toward small fish
not a predator
Required aquarium volume
from 250 L (66 gal)
Lighting
dimmed
Substrate
any (no restrictions)
Water flow
weak
Swimming level
near the bottom
Feeding
Sinking (meat / protein)
Keeping
Solitary
  • 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 (solitary), footprint, decor and tank mates.

Care and keeping

Description

In natural conditions, adult specimens of this species reach about 26 cm in length. The maximum known for the species is about 40 cm, but in an aquarium the fish grows slowly and usually stops at 25–30 cm. The catfish's body is somewhat flattened and adorned with large, fan-shaped fins. The body surface is rigid, covered with roughness and rows of sharp spines, which is reflected in the species' name. It is also worth noting that the first rays of the fins are significantly thickened, forming sharp spines, which are also studded with small prickles. One of the characteristic features of its appearance is the presence of rounded dark spots evenly distributed over the entire body. The coloration also varies, ranging from yellowish to almost black tones, depending on the specific geographical origin. The catfish's mouth, located on the underside of the head, is a sucker. Its few but very strong teeth are perfectly adapted for cracking the shells of river mollusks.

Habitat

The species is endemic to Brazil and inhabits the Amazon River basin, including the Rio do Pará region. In nature, the fish live in rivers with clear water and slow currents. As natural shelters, they prefer areas with snags and rocky bottoms, where they spend daylight hours, showing activity mainly during the night.

Behavior and Compatibility

It should be noted that the behavior pattern of these catfish is quite complex. The Spiny Pleco exhibits pronounced territorial instincts. If two adult individuals are not provided with enough space, conflicts and mutual aggression are inevitable. Similar difficulties will arise when cohabiting with other territorial fish species. For comfortable keeping of a single catfish, it is recommended to provide it with a minimum aquarium bottom area of 0.6 m². Provided this requirement is met, hostile manifestations are generally not observed. This catfish is peaceful towards fish of comparable size that inhabit the upper or middle water layers.

Care and Maintenance

For keeping a single adult Ornate Pleco, an aquarium of 250–300 liters will be optimal, provided its bottom area reaches the aforementioned 0.6 square meters (for example, 120×50 cm). It is desirable to include various appropriately sized shelters in the decor — these can be large snags, rock formations, boulders, or artificial caves. The fish show the highest activity under subdued lighting, especially after the main lights are turned off. If light intensity is not critical for other aquarium inhabitants and plants, you can initially set up dim lighting or create shaded areas using floating plants. Acclimated individuals can successfully adapt to a fairly wide range of water parameters, especially pH and dGH. However, slightly acidic or neutral water conditions of medium hardness are considered most comfortable. Long-term and successful keeping largely depends on the aquarist's ability to maintain a stable habitat that meets the needs of this species. Regular aquarium maintenance activities, as well as the uninterrupted operation of all equipment, and especially the filtration system, are crucial for achieving this goal.

Diet

In natural conditions, the diet consists mainly of various invertebrates, such as mollusks, worms, aquatic insects, and their larvae. In the absence of familiar food, these catfish can feed on various plants, fallen fruits, and other plant organic matter. Overall, it is an omnivorous species, but its diet is dominated by protein components. In a home aquarium, sinking dry foods with high protein content should be offered, as well as live or frozen foods, such as bloodworms, pieces of mussels, and shrimp. As additional components, vegetable fragments such as cucumber, zucchini, or eggplant can be used.

Breeding and Reproduction

Breeding in aquarium conditions is difficult and requires the creation of specific conditions. Spawning occurs in prepared enclosed shelters, which the male actively guards. Fry grow slowly and require quality nutrition and stable water parameters for successful development. Due to the territorial behavior of the parents, the breeding tank must provide a sufficient number of hiding places.

Diseases

This species is characterized by high sensitivity to water quality, particularly to the accumulation of nitrogenous compounds. If keeping conditions are violated, bacterial infections of the skin and fins are possible. Prevention includes regular water changes, powerful filtration, and maintaining substrate cleanliness. Due to the presence of sharp spines on the fish's body, caution should be exercised during transportation and transfer to avoid injury.

How to choose

When purchasing, choose active individuals with clean fins and no visible body damage. It is important to ensure there is no sunken belly, which may indicate emaciation or internal parasitic diseases. In the store, the fish often behave secretively, so it is worth asking the seller to gently lift decorations to inspect the catfish. The territorial nature of the species should be considered, and multiple individuals should not be acquired for keeping in a limited volume.

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 Spiny Pleco get?

An adult reaches 26 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Spiny Pleco need?

The recommended volume is 250 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Spiny Pleco need?

Temperature 23–28 °C, pH 5.8–7.5, 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 Spiny Pleco live?

Around 12 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Spiny Pleco aggressive?

Temperament: territorial (often aggressive). Keep this in mind when choosing tank mates.

How many Spiny Pleco should be kept together?

Recommended setup: solitary. Ignoring this is a common cause of stress and disease.

What does Spiny Pleco eat?

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

What is the scientific name of Spiny Pleco?

The scientific name of the species is Pseudacanthicus spinosus, family Armored Catfishes (Loricariidae). It also appears in the literature as: Hypostomus spinosus.

Similar fishes

Matched by family, categories and overlapping keeping conditions

Royal Tiger Pleco

Royal Tiger Pleco

Hypancistrus sp. L066

Armored Catfishes (Loricariidae)

The Royal Tiger Pleco, scientifically known as Hypancistrus sp. L066, belongs to the family Loricariidae, or Armored Catfishes. Its natural habitat is South America, where it is primarily found in the Brazilian state of…

Leopard Pleco

Leopard Pleco

Pseudacanthicus cf. leopardus

Armored Catfishes (Loricariidae)

The leopard pleco, scientifically known as Pseudacanthicus cf. leopardus (also called L114 and LDA007), belongs to the armoured catfish family, Loricariidae. Though its exact classification remains uncertain, this has…

Ancistrus Claro

Ancistrus Claro

Ancistrus claro

Armored Catfishes (Loricariidae)

Ancistrus claro belongs to the family Loricariidae, the armoured catfishes. Its scientific name comes from the Claro River, a small tributary of the Cuiabá in Mato Grosso, Brazil, where the species was first found. This…

Royal Panaque

Royal Panaque

Panaque nigrolineatus

Armored Catfishes (Loricariidae)

The Royal Panaque, scientifically named Panaque nigrolineatus, belongs to the family Loricariidae, which comprises armoured catfish. This large fish stands out for its striking appearance and adaptability, though its…

Other scientific names and conservation status

Other scientific names
Hypostomus spinosus
Categories
Catfish
Conservation status
Least concernLC