Weeks Bichir

Polypterus weeksii - the mottled or Weeks' bichir - is a nocturnal, air-breathing 'upper-jawed' bichir of the Congo basin reaching about 54-55 cm (SF: 550 mm SL; TankBud: 54 cm). Profile sizeCm=60 is close to adult reality once standard-length vs total-length measurement is accounted for. It hunts by smell after dark, rests in cover by day, and is one of the hardier large bichirs - though most specimens are wild-caught (SF). Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

SF records 550 mm SL and TankBud 54 cm, so profile sizeCm=60 is within normal measurement tolerance (SL excludes the caudal fin) and needs no correction. The fish grows toward that half-metre-plus adult size, so the 150 cm floor requirement should be in place well before adulthood. Broad-headed and heavy-bodied, it uses floor length rather than tank height. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

Nocturnal: SF calls it 'an incredibly hardy, nocturnal species with very poor vision' that emerges from daytime refuges to hunt. TankBud records social behaviour as 'Solitary' but offers no numeric group size, so groupSize is omitted; SF's stocking guidance is tankmate-based rather than group-based. behaviorFlags: nocturnal, solitary, cave-dweller (SF hiding places/daytime refuges; TankBud rock caves). Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

SF's adult minimum is a 150 x 60 cm base (~540 L); TankBud says 'at least 600 liters' (159 gal) - profile 500 L is marginally under both, but the 500-600 L spread is not material, so tankSizeMinL is left unchanged. SF records temperature, pH and hardness as 'not recorded'; TankBud gives 24-28 °C and pH 6.2-7.8, which bracket the profile's 24-30 °C / 6.5-7.5 - no correction proposed. Set up soft sand with driftwood, rock caves and open resting space, gentle to moderate flow, subdued lighting, and a heavy tight lid. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

SF: 'Floor space is more important than depth with this species', with an adult base of 150 x 60 cm and a 'very large tank' space rating. TankBud echoes the 'generous floor' requirement for a fish over half a metre long. The long, serpentine body rests on the substrate and needs a clear 150 cm run rather than tall hardscape. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

Diet is correctly recorded as carnivore: SF says it is 'carnivorous by nature and will not usually accept dried foods' and recommends meaty live or frozen items - prawns, earthworms, mussel, lancefish. TankBud adds whole prawn and large sinking carnivore items, and notes feeding with tongs makes for good viewing. Because it finds food by smell and eats anything fitting its mouth, remove uneaten meaty food promptly. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

SF: 'Not to be trusted with tankmates it can fit in its mouth but is relatively peaceful otherwise', listing suitable companions - other Polypterus, Datnioides, knife fish, larger Synodontis, Ctenopoma, medium-to-large characins and African butterfly fish. TankBud: house it alone or with equally large, sturdy fish. Hence communitySuitability=CONDITIONAL; invertebrates small enough to swallow are documented wild prey. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.

A Weeks' bichir is a manageable monster: 150 x 60 cm floor, heavy tight lid (SF: known jumper; TankBud: large bichirs still climb out), soft sand and nocturnal meaty feeding. Profile values are largely sound - only temperament is questioned, as both SF ('relatively peaceful otherwise') and TankBud ('Mostly peaceful') read calmer than 'Semi-aggressive'. The main research gaps are bioload, hardness data and maintenance sensitivity; with quarantine for wild-caught arrivals it is a rewarding specialist species for big, secure tanks. Confidence note: medium-confidence guidance drawn from published species care information; treat as conservative guidance, not a precise requirement.