Grandis Pencilfish

Nannostomus grandis lives up to its name as the largest member of the genus, reaching up to 6 cm — notably bigger than most pencilfish in the hobby. It displays a bold, clearly defined dark lateral stripe from snout to caudal base, overlaid on a pale cream-gold background, with red-orange fin accents in breeding males. Despite its larger size, it retains the characteristic slender pencilfish body plan.

Because of its size, N. grandis appreciates a slightly larger aquarium than smaller Nannostomus species. It is nonetheless fully peaceful and schools comfortably with other medium-sized soft-water Amazonian fish. Planted tanks with open swimming areas, some surface cover, and soft acidic water suit it perfectly.

This species is a reliable feeder that accepts a wide range of foods: quality flake, pellets, and frozen foods such as bloodworm, brine shrimp, and daphnia. Regular live-food supplementation maintains peak colouration and condition.

Water: 23–28°C, pH 5.0–7.0, soft to moderately soft (GH 1–12, KH 0–6); blackwater conditions preferred. Tank: 80 L minimum; well-planted with open swimming space, gentle filtration, dark substrate. Feeding: Flake, pellets, frozen bloodworm, brine shrimp, daphnia; accepts most small foods. Breeding: Egg-scatterer; condition on live foods; soft acidic water required. Compatibility: Peaceful with medium-sized soft-water fish — tetras, rasboras, corydoras, and dwarf cichlids.