The Complete Guide to Caring for Catfish: Bristlenose, Otocinclus, Corydoras & Miniature L-Number Plecos
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Catfish are some of the most fascinating and rewarding fish in the freshwater hobby. From the algae-grazing Otocinclus to the cave-dwelling L-number plecos, this group offers something for every level of aquarist. In this guide, we break down the care requirements, quirks, and breeding behaviours of four popular catfish groups: Bristlenose Plecos, Otocinclus, Corydoras, and miniature L-number Plecos.
Bristlenose Plecos (Ancistrus spp.)
Bristlenose Plecos are one of the most popular and beginner-friendly catfish in the hobby — and for good reason. Compact, hardy, and excellent algae grazers, they make a practical and characterful addition to most community aquariums.
Care Guide
- Tank Size: Minimum 80L; larger is always better
- Water Parameters: pH 6.5–7.5 | Temp 22–27°C | Soft to moderately hard
- Diet: Algae wafers, blanched vegetables (zucchini, cucumber, spinach), driftwood for grazing
- Temperament: Peaceful; males can be territorial with other plecos
- Tank Setup: Plenty of hiding spots, driftwood, and smooth surfaces to graze
- Skill Level: Beginner
- Max Size: ~12–15cm
Breeding Behaviour
Bristlenose Plecos are one of the easier plecos to breed in captivity. They are cave spawners — the male selects and guards a cave or hollow log, enticing the female inside to deposit her eggs. Once spawning occurs, the male takes sole responsibility for fanning and guarding the clutch until the fry are free-swimming. Providing multiple caves (PVC pipe sections, terracotta pots, or purpose-made pleco caves) will encourage spawning behaviour. A slight drop in water temperature or a water change mimicking a cool-season rain event can also trigger breeding.
Otocinclus (Otocinclus spp.)
Otocinclus — affectionately known as "otos" — are tiny, peaceful algae eaters that are highly sought after for planted aquariums. However, they come with an important caveat that every keeper should understand before purchasing.
Wild-Caught & Arrival Condition
Almost all Otocinclus available in the hobby are wild-caught, imported directly from South American river systems. This means they can arrive stressed, underfed, and in need of careful acclimatisation. Unlike many tank-bred species, otos have not adapted to the conditions of captivity over generations — they are pulled from rivers rich in biofilm, soft algae, and natural grazing surfaces.
A well-established, heavily planted aquarium is essential for keeping Otocinclus successfully. Tanks with abundant soft algae growth, biofilm on hardscape and glass, and live plants give otos the constant grazing opportunities they need to recover and thrive. Placing otos into a brand-new or sterile aquarium is one of the most common reasons they decline rapidly after purchase. We strongly recommend having your tank fully cycled and running for several months before adding otos, so that a healthy biofilm and algae layer has had time to develop.
Supplemental feeding with blanched zucchini, cucumber, and high-quality algae wafers is also important, particularly in tanks where natural algae is limited.
Care Guide
- Tank Size: Minimum 60L; keep in groups of 6+
- Water Parameters: pH 6.0–7.5 | Temp 22–26°C | Soft to moderately hard
- Diet: Biofilm, soft algae, blanched vegetables, algae wafers
- Temperament: Peaceful; excellent community fish
- Tank Setup: Heavily planted with driftwood, smooth stones, and established algae growth
- Skill Level: Intermediate (due to wild-caught sensitivity)
- Max Size: ~4–5cm
Breeding Behaviour
Otocinclus have been bred in captivity, though it is uncommon. Spawning is typically triggered by a significant water change with slightly cooler water, mimicking seasonal rainfall. Eggs are deposited on plant leaves and glass surfaces. Fry are extremely small and require a tank rich in biofilm and microalgae to survive.
Corydoras (Corydoras spp.)
Corydoras are beloved for their social nature, endearing behaviour, and the sheer diversity of species available. While many are considered beginner-friendly, it's worth knowing that not all Corydoras are created equal.
Not All Corydoras Are Beginner Fish
Common species like Corydoras paleatus (Peppered Cory), C. aeneus (Bronze Cory), and C. sterbai are robust and well-suited to beginners. However, many wild-type and rarer species — such as C. adolfoi, C. duplicareus, and various undescribed "CW" number species — can be significantly more sensitive to water quality, temperature fluctuations, and stress. These fish often command higher prices and require more experienced husbandry. If you're new to the hobby, start with a well-established captive-bred species before venturing into wild-type or rare Corydoras.
Care Guide
- Tank Size: Minimum 80L; keep in groups of 6+ of the same species
- Water Parameters: pH 6.0–7.5 | Temp 22–26°C (species-dependent) | Soft to moderately hard
- Diet: Sinking pellets, frozen bloodworm, daphnia, brine shrimp, blanched vegetables
- Temperament: Peaceful; excellent community fish
- Tank Setup: Soft sand substrate (essential — gravel damages their barbels), shaded areas, driftwood
- Skill Level: Beginner to Intermediate (species-dependent)
- Max Size: 2.5–8cm depending on species
Breeding Behaviour
Corydoras are one of the most rewarding catfish to breed, and many species will spawn readily in a well-maintained aquarium. One of the most fascinating triggers for Corydoras breeding is a drop in temperature — mimicking the cool-season rains of their native South American habitats. In practice, this means performing a large water change (30–50%) with water that is several degrees cooler than the tank. This temperature drop, combined with a drop in barometric pressure during cold or stormy weather, can trigger spawning almost immediately.
During spawning, the female holds 2–4 eggs between her pelvic fins while the male fertilises them in the classic "T-position". She then deposits the sticky eggs on glass, plant leaves, or hardscape. Eggs should ideally be moved to a separate hatching container to protect them from being eaten. Fry are relatively easy to raise on microworms, baby brine shrimp, and finely crushed foods.
Miniature L-Number Plecos
L-number plecos — named for the "L" prefix used to catalogue undescribed or newly described Loricariid species — represent some of the most spectacular and sought-after catfish in the hobby. Miniature species such as the L134 (Leopard Frog Pleco), L333 (King Tiger Pleco), L397 (Alenuer Tiger Pleco), and others offer stunning patterning in a manageable size.
Wood as a Dietary Requirement
One of the most important — and often overlooked — aspects of keeping many L-number plecos is the role of driftwood in their diet. Species such as the Leopard Frog Pleco (Peckoltia compta, L134) and many other wood-eating plecos (known as xylophages) actively rasp and consume driftwood as part of their digestive process. The cellulose and microorganisms found in waterlogged wood are believed to be essential for gut health in these species. A tank without driftwood is not a suitable environment for wood-eating L-number plecos. Use natural, aquarium-safe hardwoods such as Malaysian driftwood, cholla wood, or spider wood, and replace pieces as they are consumed over time.
Care Guide
- Tank Size: Minimum 100L; species-dependent
- Water Parameters: pH 6.0–7.2 | Temp 24–29°C | Soft to moderately hard; warm, well-oxygenated water is key
- Diet: Driftwood (essential for many species), algae wafers, protein-rich sinking foods, blanched vegetables, frozen foods
- Temperament: Generally peaceful but territorial with conspecifics; avoid housing multiple males of the same species without ample space and caves
- Tank Setup: Abundant driftwood, caves, and hiding spots; strong filtration and high oxygenation
- Skill Level: Intermediate to Advanced
- Max Size: 8–15cm depending on species
Breeding Behaviour
Breeding L-number plecos is one of the most rewarding challenges in the freshwater hobby — and the results are absolutely worth the effort. Like Bristlenose Plecos, L-numbers are cave spawners. The male claims and defends a cave, coaxing the female inside to spawn. After egg deposition, the male guards the clutch fiercely, fanning the eggs with his fins to maintain oxygenation and prevent fungus.
What makes L-number breeding more challenging than common plecos is the specificity of their requirements. Water parameters must be dialled in precisely — many species require soft, warm, well-oxygenated water with a slightly acidic pH. Conditioning the fish with a high-quality, varied diet (including live and frozen foods) is essential before attempting to breed. Spawning is often triggered by a water change with slightly warmer water, mimicking the onset of the wet season in their native Amazonian or Orinoco river systems.
Clutch sizes are typically smaller than Bristlenose (often 10–30 eggs), and fry can be more delicate in their early weeks. However, successfully raising a clutch of L134s or L333s is an experience that few aquarists forget — and one that often marks the transition from hobbyist to true enthusiast.
Final Thoughts
Whether you're drawn to the approachable charm of a Bristlenose, the delicate nature of an Otocinclus, the social antics of a Corydoras group, or the prestige of a breeding pair of L-numbers, catfish offer a depth of experience that few other fish groups can match. The key to success with all of these species is the same: a well-cycled, stable aquarium, appropriate tank mates, a varied diet, and a willingness to understand the specific needs of each fish.
As always, if you have questions about any of the species we stock, our team at Chloe's Aquatic Centre is here to help.