Three-spined stickleback

Care at a glance

Overview

The three-spined stickleback is a coolwater fish that shoals in the middle of an unheated, planted tank. It suits a keeper with some experience.

Caring for the three-spined stickleback

Give three-spined sticklebacks a tank of 20 gal (75 L) or more. Run strong filtration or an airstone, since they need cool, well-oxygenated water. If you collect wild native stock, check your local rules first, and never release tank fish into the wild.

This is a coolwater fish, not a tropical one, so leave the tank unheated and hold it at 50 to 64°F (10 to 18°C). Temperatures above about 20°C stress them, so never house them with warm-water tropical fish. Most aquarists keep them in hard, slightly alkaline freshwater at a pH of 6.5 to 8.0.

Three-spined sticklebacks are carnivores that often refuse dry flake. Feed live or frozen daphnia, bloodworm, gammarus and brine shrimp.

Keep a group of at least six. Outside the breeding season they shoal peacefully in the middle of the water. In season, males turn territorial and bite and chase other fish away from their nests. A roomy, heavily planted layout or a single male cuts down on fighting.

In spring, the male's throat and belly flush bright red. He builds a tunnel-shaped nest from glued plant fibers. After the female lays, he guards the eggs alone and fans water over them until they hatch. Breeding them is moderately difficult.

Good to know

Gasterosteus aculeatus is a small fish in the family Gasterosteidae. It is anadromous, meaning some populations migrate between salt and fresh water. It is also euryhaline, able to handle a wide range of salinity, and it lives in freshwater, brackish water and full saltwater. Instead of scales, it has bony plates along the flanks.

In the wild

Three-spined sticklebacks live across the cool temperate Northern Hemisphere. They are found in coastal streams, ditches and ponds throughout Europe, northern Asia, including Japan, and North America.

Common questions

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