Oryzias woworae · Daisy's Ricefish

Overview

Oryzias woworae: Blue body sheen and orange-red fin edges make this tiny ricefish distinctive. A group reveals courtship changes, while its small size calls for gentle, undemanding companions.

Distribution & habitat

The confirmed locality is Fotuno stream on Muna Island, Southeast Sulawesi, Indonesia, though the range may be wider. Forest shade covers a karst stream with mud, sand, and leaves; fish were collected schooling in a quiet pool.

Aquarium setup

Sand, worn roots, branches, and leaves provide a naturalistic arrangement, while planted aquaria are equally suitable.Sparse surroundings can reduce display color, whereas dense growth also shelters young fish.

Diet & feeding

Use appropriately small foods, combining quality crushed flakes or fine granules with microworms and Artemia nauplii. Surface grazing has been observed in adults, suggesting but not confirming an algal component in the natural diet.

Behaviour & compatibility

Eight or more individuals form a more confident group. Choose similarly small, peaceful companions; suitable freshwater shrimp are also possible. Courting males may defend brief territories despite an otherwise gentle disposition. Use a dedicated group for breeding and avoid other ricefish species because of hybridization risk.

Sexual dimorphism

Adult males are distinctly brighter and slimmer, with longer dorsal and anal fins. Their genital papilla is a short tube, whereas females have two lobes.

Breeding

Well-conditioned females can produce eggs every few days or even daily. Spawning generally takes place early in the morning as males darken and defend small temporary spaces. Adhesive eggs are released and fertilized together. Each batch usually contains 10–20 eggs. They remain attached beneath the female temporarily, then are transferred singly or in small clusters to plants or other media. Fine vegetation and spawning mops are suitable.

Incubation usually lasts one to three weeks, depending on temperature. Adults commonly ignore eggs but eat free-swimming fry. Transfer eggs or young to a nursery filled with parental-tank water, or provide dense cover for some to survive in place. Microworms and Artemia nauplii are accepted after free swimming begins. Separate markedly different sizes of juveniles to prevent the larger ones eating the smaller.

Notes

Nuptial males of the similar Oryzias wolasi are darker and more purple. Orange pigment along the anal-fin base and into the tail is already visible in young fish of this species and helps distinguish them. Similar appearance is not a reason to interbreed them.