Taxonomy & naming
Tenellus ternetzi was described by Carl H. Eigenmann in 1925 in another genus, and is valid in the Catalog of Fishes. It belongs to the Doradidae, the thorny or talking catfishes, and to the small genus Tenellus. Wet Spot has sold it under its scientific name.
Morphology
FishBase gives a maximum length of 5 in SL for males or unsexed fish. Like other doradids it has bony plates along the flank and a stout, locking spine in the dorsal and pectoral fins, which can tangle in nets and cut the hand.
Habitat
FishBase records the species from the Amazon River basin as freshwater, demersal and tropical. The type locality is the Rio Tapajos at Santarém in Brazil. No temperature, pH or hardness figures are recorded.
Feeding
No diet is recorded for this species. Doradids as a group forage along the bottom at night for invertebrates and plant matter.
Mating
Courtship has not been described.
Breeding
No spawning or egg information is recorded, and aquarium breeding is not documented.
In the aquarium
At under 5 in SL it fits a medium tank with a soft substrate, caves and wood, and it is best fed after lights-out with sinking pellets and frozen foods. Move it with a container rather than a net, since the spines catch. No water-chemistry targets are published for it.
Conservation
IUCN assessed Tenellus ternetzi as Least Concern on 6 August 2020. No specific threat is recorded.