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FisheasyFreshwater

Porthole Catfish

Dianema longibarbis

Also known as Flagtail Porthole Catfish

AnimaliaChordataActinopterygiiSiluriformesCallichthyidae

📍 Rio Negro & Rio Madeira, Brazil

The Porthole Catfish is a slender, elongated catfish reaching around 10 cm (3.9 in), featuring a beige to tan body adorned with rows of small dark spots along the flanks and a distinctive pattern of long barbels around the mouth. It is a peaceful, social species that spends most of its time near the substrate and lower water column, making it an excellent cleanup crew member in community aquariums.

Size4"
Min Tank30g
School4+
peaceful
Zonebottom

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Care Guide

Diet

Porthole Catfish are omnivores that accept a wide variety of foods including high-quality sinking pellets, wafers, and bottom-feeder tablets as a dietary staple. They benefit greatly from regular supplementation with frozen or live foods such as bloodworms, tubifex, and daphnia to encourage optimal health and coloration. Occasional offerings of blanched vegetables like zucchini or cucumber are also accepted and provide useful dietary variety.

Behavior

Porthole Catfish are highly social and should be kept in groups of at least four to six individuals, as solitary specimens tend to become shy and stressed. They are most active during dawn and dusk, spending much of the day sheltering among driftwood, leaf litter, or dense vegetation near the substrate. They are completely non-aggressive and will not bother tankmates of any size, making them ideal for peaceful community setups.

Breeding

Breeding Porthole Catfish in captivity is possible but relatively uncommon compared to other callichthyids. Unlike many related species, they are bubble nest builders; the male constructs a floating nest of bubbles and plant material at the water surface, into which the female deposits eggs. The male guards the nest, and eggs typically hatch within 3-4 days; fry should be fed infusoria and finely powdered foods initially, and water quality must be kept pristine during this period.

Common Diseases

Ich (White Spot Disease)

Symptoms

Fine white spots resembling grains of salt covering the body and fins, flashing against surfaces, lethargy, and loss of appetite.

Treatment

Raise water temperature gradually to 28-30 C to accelerate the parasite lifecycle, and treat with a copper-based or formalin-based ich medication; avoid medications containing scaleless-fish warnings as callichthyids can be sensitive.

Red Blotch Disease (Bacterial Hemorrhagic Septicemia)

Symptoms

Red streaks or blotches on the body and fins, ulcers, lethargy, and loss of appetite; often triggered by poor water quality.

Treatment

Perform immediate large water changes to improve water quality, identify and eliminate the stressor, and treat with a broad-spectrum antibiotic such as kanamycin or nitrofurazone.

Fungal Infection

Symptoms

White or gray cotton-like growths on the body, fins, or around the mouth, often secondary to physical injury or poor water conditions.

Treatment

Improve water quality with frequent water changes, remove any decaying organic matter, and treat with an antifungal medication such as methylene blue or a commercial antifungal product safe for scaleless fish.

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Quick Facts

diet
Omnivore; sinking pellets, frozen and live foods
lifespan
5-8 years
max size
10 cm (4 in)
tank size
30 gallons minimum

Water it likes

ph
6.0-7.5
ammonia
0 ppm
nitrate
<20 ppm
hardness
2-12 dGH
temperature
72–82°F (22–28°C)

Legality

No state or federal restrictions on record for this species.

Not legal advice, and possibly incomplete or out of date. Rules vary by state and locality and change over time — always confirm the current regulations with your state wildlife or agriculture agency before buying, keeping, or shipping this species.

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Kept by0 hobbyists