Taxonomy & naming
Synodontis filamentosus Boulenger, 1901 is the valid name in the Catalog of Fishes, described from the mouth of Lake No on the White Nile in Sudan. The epithet is Latin for 'bearing a filament', which fits the extended dorsal-fin ray.
Morphology
Like other squeakers, it has a broad head, three pairs of barbels (an unbranched maxillary pair and two branched mandibular pairs), an adipose fin and a stout, serrated, lockable spine at the front of the dorsal and each pectoral fin. The skin is scaleless. The spines tangle in nets and can pierce skin, and rubbing the pectoral spine against the girdle makes the audible squeak that gives the group its name. FishBase gives a maximum of 10 in SL, and cites a second source with a largest specimen of 9 in SL and 11 in TL.
Habitat
FishBase gives its range as the Nile, Niger (including the Benue), Volta and Chad basins. It is a freshwater, benthopelagic tropical fish, and the type locality is on the White Nile in Sudan.
Feeding
Synodontis are opportunistic omnivores that forage mostly at night, taking insect larvae, small crustaceans, molluscs, detritus and plant material. Diet specifics for this species have not been described. In the aquarium the genus takes sinking pellets, wafers and frozen foods readily, best offered after lights-out.
Mating
FishBase says it is oviparous with distinct pairing during breeding. Where Synodontis have been studied, spawning is a pair or group event in sheltered sites, with eggs left unguarded or only loosely guarded.
Breeding
FishBase lists it as oviparous with distinct pairing. Breeding in aquaria has not been recorded; most Synodontis are not bred routinely by hobbyists, and commercially available fish are generally wild-caught.
In the aquarium
Keep it in a roomy tank with caves, wood or rock stacks to retire to by day, a fine substrate, and tankmates too large to be eaten and robust enough to ignore the spines. Net with a container, not a mesh net, to avoid tangling. Medicate cautiously, as scaleless skin is sensitive. FishBase lists 70–75 °F and pH 6.0 to 7.5, with hardness up to 25 dH.
Conservation
The IUCN Red List assessed it as Least Concern in 2019, meaning it is not considered at risk of extinction at present. Wild-caught fish enter the trade, but the effect on wild populations has not been described.