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his month we have another no-no catfish for your aquarium: the "Silond catfish", Silonia silondia. This species is from the new family Ailiidae, which Wang et al. detached from the family Schilbeidae, reclassified, and moved in 2016. As of 2026, this small family has 7 genera and 13 species.

    Silonia silondia

This is an extract from Indian aquarist and ichthyologist Abhisek Mishra on keeping this species. "Biggest of the ailiid catfish family, with maximum length reaching up to 6ft. Maximum-size specimens are rare to find these days due to overfishing and polluted river stretches. An apex predator in a true sense, with big eyes and sharp teeth protruding out of the jaws, it's a vicious-looking fish. Not many people know about it outside the angling community because they are very sensitive when taken out of water and don't survive for long. You won't find this fish anywhere in the aquarium hobby. I am lucky to have this beautiful species in my collection after so many failed efforts. It prefers smaller fish and shrimps as prey, and I have been successful in feeding it".

"Silonia relies completely on its eyesight and will require a live feed to settle in. Afterwards, I was succesfull to handfeed frozen shrimps and worms. Ailiidae is a very under-documented family of catfish, and their behaviours are almost unheard of in the hobby, so everything has been self-learning through repeated failures. They are definitely one of the most interesting families of cats to keep, and I will recommend anyone who finds a chance to keep them".

Silond catfish

Ageniosus lurida, Pimelodus silondia, Silonia lurida, Silundia gangetica

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Asia: Northern India, Bangladesh, Myanmar and Nepal. Type locality: Gangetic estuaries.

160.0cm. SL (63ins)

23-26°C (73-79°F)

Rayed dorsal fin inserted above half of the pectoral fin, spine slender, rugose anteriorly and serrated posteriorly on its upper portion. Adipose fin very short, well separated from caudal base. Pectoral fin reaching pelvic fins in young and half-grown juveniles; but in adults it does not; spine serrated along inner edge. Pelvic fins reaching anal opening. Anal fin long, not reaching caudal fin base. Least height of caudal peduncle 1.4 to 1.7 in its length. Caudal fin forked, lobes equal.

Not suitable for aquarium keeping.

Oviparous, eggs are unguarded. Spawns in the rainy season and is said to migrate upstream to the area of the upper tributaries.

Not recorded.

Large specimens have abundant curved teeth in their jaws and feed on fishes. Smaller specimens feed on invertebrates.

Adipose fin: Fleshy finlike projection without rays, behind the rayed dorsal fin.
Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.
Caudal fin: The tail.
Caudal peduncle: The narrow part of a fish's body to which the caudal or tail fin is attached.
Dorsal fin: The primary rayed fin(s) on top of the body.
Opercle: The bony covering of the gills of fishes.
Oviparous: Describing a species that lays eggs.
Pelvic fins: The paired fins, between the pectorals and the anal fins (also referred to as ventrals).
Pectoral fin: The paired fins just behind the head.
Ruguse: Covered in ridges, knobs or protuberances, deeply wrinkled etc.
Vestigial: These leftover pieces show what an animal's or human's ancestors looked like or how they lived long ago.

Silonia: Etymology not explained, possibly latinisation of silon, local name for juveniles of this catfish in Bihar, India, or putative tautonymy with Pimelodus silondia but missing the “d”.
silondia: Latinisation of Silond, local name for this catfish in Bihar, India.

Photo Credits

© Abhisek Mishra.
© Nonn Panitvong.
Map: Sadoff et al.