Porthole Catfish
Dianema longibarbis
A peaceful, social catfish related to corydoras that swims at all levels.
| Difficulty | Beginner |
| Min. Tank Size | 110 L |
| Temperature | 22.0–26.0 °C |
| pH Range | 6.0–7.5 |
| Max Size | 12.0 cm |
| Lifespan | 8-10 years |
| Diet | Omnivore |
| Temperament | Peaceful |
Overview
The Porthole Catfish (Dianema longibarbis) is a peaceful, social catfish related to corydoras that swims at all levels. It is a popular choice among Australian aquarists, reaching around 12 cm and living roughly 8-10 years when properly cared for.
This complete guide covers how to keep the Porthole Catfish successfully - tank size and setup, water parameters, the best foods (including recommended brands), suitable tank mates, breeding, sexing and the health issues to watch for. It is rated Beginner to care for.
Natural Habitat & Origin
This catfish comes from the rivers and streams of South America or Africa, foraging along the bottom for food. It appreciates hiding places, soft substrate and clean, well-oxygenated water.
Matching the temperature, water chemistry and cover a species evolved with is the simplest route to keeping it healthy and seeing its natural behaviour and colour.
Tank Size & Aquarium Setup
Provide a minimum of 110 litres for the Porthole Catfish. As a group-living species, swimming length and floor space matter more than height.
Include driftwood and caves for shelter; wood aids digestion for many plecos and gives bottom-dwellers somewhere to feel safe by day.
Always add fish only to a fully cycled, mature tank with stable biological filtration. Match filtration generously to the fish's size and waste output.
Water Parameters
Keep the Porthole Catfish in stable water at 22-26 °C with a pH of 6.0-7.5. It adapts to a moderate range, so stability matters more than an exact figure.
Test regularly: ammonia and nitrite must read zero, and nitrate should be kept low with routine partial water changes. Always dechlorinate and temperature-match new water, because sudden swings cause far more illness than water that is stable but slightly imperfect.
Diet & Feeding
The Porthole Catfish is an easy-going omnivore that accepts a wide range of foods.
In Australia, good options include Hikari Sinking Wafers and Vibra Bites, API Bottom Feeder pellets and Dymax frozen bloodworm. Feed small amounts once or twice a day (only what is cleared in a minute or two), vary the diet for the best colour and health, and avoid overfeeding, which is the leading cause of poor water quality.
Temperament & Tank Mates
The Porthole Catfish is peaceful and community-friendly. It mixes well with other calm species that share its temperature (22-26 °C) and pH (6.0-7.5) needs, are too large to be eaten and not large enough to eat it.
It is happiest in a group of its own kind and is shyer and less settled when kept alone.
Breeding
The Porthole Catfish is a bubble-nest builder. The male builds a raft of bubbles at the surface, entices the female beneath it, then guards the eggs and fry himself.
Even if you are not planning to breed it, recognising this behaviour helps you understand what you are seeing and respond well - for example by adding cover for fry or giving a guarding pair extra space.
How to Tell Males from Females
Females are generally rounder and fuller-bodied; in many Synodontis and similar catfish, visual sexing is difficult outside breeding condition.
Common Health Problems
Scaleless and fine-scaled fish like this react badly to poor water and to copper-based or full-dose medications, so treat at half strength. They are also among the first to show ich. Quarantine new arrivals for 2-4 weeks and watch daily for early signs such as loss of appetite, unusual hiding, clamped fins or laboured breathing - caught early, most issues are very treatable.
Prevention beats cure: keep water pristine, avoid overstocking and overfeeding, quarantine new arrivals, and act at the first sign of trouble.
Is the Porthole Catfish Right for You?
The Porthole Catfish suits beginners and experienced keepers alike, as long as you can provide at least 110 litres, water at 22-26 °C and pH 6.0-7.5, the right diet and a proper group of its own kind.
Meet those needs and the Porthole Catfish will reward you for around 8-10 years. Use our free aquarium calculators to plan your setup, and explore our other fish, plant and disease guides to build a thriving aquarium.
