Taxonomy & naming
Auriglobus silus was first described by Tyson Roberts in 1982, originally placed in the genus Chonerhinos, which historically housed several freshwater puffers of the Indo-Pacific. In 1999 Maurice Kottelat revised the group and erected the genus Auriglobus to receive the golden puffers, making the current valid combination Auriglobus silus (Roberts, 1982) — the parenthetical authority signals the transfer out of Roberts's original genus. The Catalog of Fishes (Eschmeyer, CAS) is the governing authority for this placement.
The broader taxonomy of Asian puffers underwent sweeping revision from the 1990s onward. The old catch-all genus Tetraodon, once applied to puffers worldwide, is now restricted to African species. Asian freshwater and brackish puffers were redistributed across Dichotomyctere (the green spotted, figure-eight and topaz puffers), Pao (Mekong river puffers), Leiodon (ocellated puffer), Carinotetraodon (dwarf puffers) and Auriglobus. A. silus can be confused in the trade with its congener A. modestus; A. modestus is larger (to about 4 in) and has a less steeply sloping snout and a less prominent lower jaw.
Morphology
A. silus is a compact, torpedo-shaped puffer reaching a maximum of 3 in standard length, though trade specimens are typically 1.5–2 in. The body is deeper than it is wide, covered in fine prickles rather than true scales — the skin is tough and spiny, a puffer characteristic that makes these fish unusually sensitive to copper and many other dissolved medications. The snout slopes more steeply than in related species, and the lower lip protrudes noticeably, two features that help separate it from A. modestus in the absence of formal measurements.
The four fused teeth form the beak that is the defining feature of the family Tetraodontidae. The beak is divided by a central suture into two upper and two lower cusps, producing a parrot-like cutting edge well suited to cracking snail shells and crustacean carapaces. This beak grows continuously throughout the fish's life. The belly is capable of inflating with water as a defensive mechanism — a response to threat that should never be triggered deliberately in captivity, and the fish should never be lifted into air, as it may gulp air instead of water, which can be fatal.
Habitat
A. silus is a freshwater species native to the islands of Borneo and Sulawesi in Indonesia, with FishBase also recording it from Kalimantan (the Indonesian portion of Borneo). Despite its placement in the hobbyist grouping of 'brackish puffers' and occasional claims of brackish tolerance, natural history records do not support a tidal or estuarine distribution: the species occupies freshwater rivers and streams, not mangrove creeks or estuaries.
Specific habitat parameters from its native waters are not well documented in the accessible literature. Given the geography — lowland rivers of Borneo and Sulawesi — the fish likely inhabits warm, soft-to-moderately-hard water with neutral to slightly acid pH, typical of Sundaland river systems. Trade import records from Thailand suggest additional collection points in mainland Southeast Asia, though the extent of the natural distribution there remains unclear.
Feeding
A. silus is a durophage — a hard-food crusher — consuming molluscs, crustaceans and insects as the core of its diet, supplemented with algae and seeds according to stomach-content data compiled on FishBase. The beak is purpose-built for this lifestyle: the fused-tooth cusps exert enough force to crack snail shells and crush small bivalves and crustaceans whole.
In the aquarium this dietary profile is non-negotiable. The fish must receive hard-shelled prey — live or frozen snails, small shellfish, cockles, mussels and small crustaceans — as a regular part of every feeding. Without abrasive, shell-cracking meals the beak overgrows continuously, eventually preventing the fish from feeding at all and requiring veterinary trimming under anaesthetic. Soft foods alone will not maintain beak condition. Supplementary items can include insect larvae and other meaty invertebrates, but the snail component is essential.
Mating
The reproductive behaviour of A. silus in the wild is essentially unrecorded. One aquarium observation documented eggs laid on the glass wall of a captive tank, suggesting the species deposits adhesive or semi-adhesive eggs on a firm substrate rather than scattering them freely — an observation consistent with substrate-spawning tendencies seen in some freshwater puffers — but the full sequence of courtship and spawning has not been described in the published literature.
Whether males display territorially before spawning, how pair formation proceeds, and whether the species spawns once seasonally or opportunistically throughout the year are all open questions. The data gap is real and should not be papered over: almost nothing is known about the mating behaviour of this species in either wild or captive settings.
Breeding
Successful breeding of A. silus in captivity is rare and minimally documented. The single reported aquarium observation — eggs on the glass — indicates oviparous reproduction with external fertilisation, which is consistent with the family broadly, but no detailed spawning report with confirmed hatching and fry-rearing appears in the hobby literature.
Given the data gap, facts.breeding reflects what is honest: the mode is not documented well enough to characterise, and parental care, if any, is unknown. Hobbyists who achieve spawning are encouraged to document and share the outcome; the species' care requirements in captivity (see In the aquarium) and the general rarity of successful tetraodontid breeding in home tanks make any verified account valuable.
In the aquarium
A. silus is recommended for experienced hobbyists rather than beginners. Its core requirements follow from its biology. The beak grows continuously and must be worn down by hard-shelled food — live snails and small shellfish are the backbone of the diet; without them the beak overgrows and the fish cannot feed. Strong mechanical and biological filtration is essential: puffers are messy, heavy-eating fish that produce significant waste, and water quality must be maintained with large, regular water changes.
Temperament is an important factor in stocking decisions. A. silus has been observed coexisting with conspecifics with minimal aggression when kept as juveniles in a heavily decorated tank with plentiful sight breaks, but individuals may become more intolerant as they grow. The species is best treated as a solitary specimen or kept in a well-furnished species tank; it should not be trusted in a general community. As with all puffers, copper-based medications are toxic and must never be used — puffers lack true scales and gill covers, making them acutely sensitive to dissolved copper and many other chemicals. Dosing of any medication should be done with care and at reduced levels.
The fish should never be deliberately provoked into inflating, and must never be lifted out of the water into air: air inflation can be lethal. Its organs and skin carry tetrodotoxin and should not be handled carelessly; the same toxin makes the fish dangerous to eat. Despite these caveats, hobbyists who provide the right environment — warm freshwater, heavy feeding with hard-shelled prey, good filtration and an uncrowded tank — find A. silus a characterful and interactive fish.
Conservation
Auriglobus silus is assessed as Near Threatened (NT) on the IUCN Red List, assessed 18 December 2019 and published 2020. The NT listing reflects concern about ongoing habitat degradation across its range in Borneo and Sulawesi — deforestation, agricultural run-off and river modification affecting lowland freshwater systems throughout the Indonesian archipelago — without yet reaching the threshold for a Vulnerable listing.
Collection for the aquarium trade likely exerts some pressure, though the extent of wild harvest versus incidental collection during broader fishery operations is not well quantified. The species' restriction to two island systems (Borneo and Sulawesi) limits the buffering effect of a wide continuous range. Continued monitoring of lowland river habitats in Kalimantan and Sulawesi, and better documentation of population sizes and trends, would inform future assessments. The tetrodotoxin content of the flesh makes A. silus of no food-fish interest, removing one pressure that affects many other freshwater fish in the region.