Shadow catfish (Hyalobagrus flavus) care guide

Group
Freshwater fish
Other names
Shadow catfish
Family
Bagridae (bagrid catfishes)
Origin
Indonesia: known only from the Batang Hari drainage in Sumatra and the Mentaya basin in southern Borneo, usually hiding under thick mats of floating grass.
Water
freshwater
Maximum size
4.4 cm
Temperature
22–27°C
pH
5–6.2
Hardness
Soft (exact figures not given by sources)
Minimum tank
54 litres
Care level
intermediate
Temperament
peaceful

Care

A tiny, partly see-through bagrid catfish that, unusually for a catfish, is active by day and shoals in midwater. PlanetCatfish says it should be kept in groups of four or more; a group of six or more of the one species is better and makes the fish bolder. In the wild it hides under thick mats of floating grass, and PlanetCatfish recommends a heavily planted tank. Floating plants to dim the light, plenty of stem plants and some wood make it feel secure. It prefers little or no current, so keep filtration gentle. Neither source gives a tank size; a tank of about 60 × 30 cm (around 54 litres) for a small group is our estimate. It comes from soft, acidic water: PlanetCatfish gives 22–27 °C and pH 5.0–6.2. Keep the water clean and stable with regular small partial water changes; it is not a fish for hard, alkaline tap water. Identification and sexing: a small, slim, translucent yellowish fish with a dark stripe along the side. PlanetCatfish notes that among the imported Hyalobagrus species it is the only one with serrations on just the front half of the pectoral spine. Males are slimmer and have a long genital papilla just in front of the anal fin; ripe females can be recognised by the greenish eggs visible through the body wall. The name comes from Greek hyalos, transparent, and Latin flavus, yellow. It is only occasionally available. FishBase and PlanetCatfish list it as Data Deficient on the IUCN Red List (assessed 2019). Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=295); FishBase (fishbase.se/summary/Hyalobagrus-flavus.html). Checked October 2026.

Diet

A small micro-predator. It prefers live and frozen foods such as Daphnia, brine shrimp, cyclops and small bloodworm, and will also take small prepared foods such as micropellets once settled. Feed small amounts often, and make sure it is not outcompeted by faster fish.

Breeding

PlanetCatfish records that it has been bred in the aquarium. It is an egg-layer that sticks its eggs to leaves. Condition a group on live foods in a well-planted tank with soft, acidic water; ripe females show greenish eggs through the body. Remove eggs or adults after spawning, and start the fry on infusoria or very fine foods, moving on to newly hatched brine shrimp.

Compatibility and tank mates

A peaceful, diurnal shoaling fish for a quiet tank of small, gentle species such as small rasboras, Boraras, small gouramis and small loaches. Avoid boisterous or large fish, which will intimidate it and take its food.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

About Aquatic-Auctions

  • Aquatic-Auctions (aquatic-auctions.com) is a UK online marketplace for aquarium and pond livestock and equipment: tropical and marine fish, corals, shrimp, snails and other invertebrates, aquatic plants, tanks, filtration, lighting and food.
  • Items are sold by auction, buy it now or classified advert, by hobbyist and business sellers in the UK.
  • Buyers pay sellers directly; Aquatic-Auctions does not hold the money. Hobbyist sellers can only take PayPal or cash on collection. Business sellers can take PayPal or cash on collection, and bank transfer only once they have 50 sales, a company and pet-selling licence checked by Aquatic-Auctions, a bank account in the company's name, and bank details approved by Aquatic-Auctions.
  • Buyers are told to pay by PayPal Goods & Services, never PayPal Friends and Family, gift cards or crypto.
  • Live fish and other vertebrates must be sent by specialist live-animal couriers (for example APC Overnight or DX Express), never by Royal Mail. Some invertebrates and plants may go by Royal Mail Special Delivery or 1st Class within its rules.
  • Banned and invasive species (for example those on the GB invasive species lists) cannot be listed, and sellers must meet the site’s animal welfare standards.
  • Members must be 16 or over to buy (16 and 17-year-olds with a parent or guardian’s agreement); sellers must be 18 or over.
  • Business sellers show their address, company details and pet-selling licence to buyers. Seller ratings run from 0 to 100: +1 for each positive feedback, −1 for each negative.
  • The site includes a free community species wiki with care guides (water parameters, tank size, diet, temperament, breeding).
  • Aquatic-Auctions is run by Etavonni Tech Limited trading as Aquatic-Auctions (company number 10204188), Aldershot, Hampshire, UK. Contact: [email protected].