Round-tailed Paradise Fish

Macropodus ocellatus, the round-tailed or Chinese paradise fish, is a cold-tolerant labyrinth fish found across eastern China and Korea in ponds, ditches, and slow-moving streams. It is distinguished from the common paradise fish by its rounded caudal fin and somewhat less gaudy colouration, though males still display impressive blue and red vertical banding.

This species can tolerate temperatures as low as 10°C, making it suitable for unheated aquariums in temperate climates. It is one of the few labyrinth fish that can be kept outdoors in mild regions during summer months. Despite its hardiness, it remains semi-aggressive — males should be kept one per tank or with sufficient space and visual barriers.

M. ocellatus is an accomplished bubblenest builder. It is more readily available from specialist labyrinth fish dealers and represents an excellent cold-water alternative to the common paradise fish. Its adaptability and resilience make it a good choice for beginners in cooler climates.

Water: 15–24°C, pH 6.5–7.5, soft to moderately hard — tolerates cool temperatures unusually well. Tank: 60 L with dense planting; can be kept in unheated tanks in temperate environments. Feeding: omnivorous — flake, pellets, live and frozen foods including earthworms and insects. Breeding: prolific bubblenester; male guards nest aggressively; remove female after spawning. Compatibility: keep one male per tank; compatible with robust, similar-sized cool-water fish.