Blue Tetra (Boehlkea fredcochui): Ultimate Care Guide


Blue Tetra (Boehlkea fredcochui), also known as Cochu’s Blue Tetra, is a tropical fish that is native to the Amazon Basin. Not to be confused with the Blue Tetra (knodus borki) of Peru, the Cochu’s Blue Tetra is found in rivers and streams throughout Colombia and Brazil.

The Cochu’s Blue Tetra is a smaller species of tetra that is blue in color, and its blue pigmentation varies in intensity according to its health condition and sex. Although its fins and body are mostly translucent, this fish is known for its signature blue coloration that may reflect hues of pink, creating an iridescent effect that enhances its effervescent shimmer.

Blue Tetra Care

When adding a filter to the blue tetra’s tank, it’s best to use a gentle water filter that’s not too powerful, sponge filters are a good option. To maintain the quality of the water in the blue tetra’s tank, 10% of the water should be changed once a week, or 25% every two weeks. Blue tetras appreciate plants and driftwood that offer dark hideouts, as long as the decor doesn’t take up too much of their space to swim. Because blue tetras are partial to a dimly lit environment, it’s a good idea to supply their tanks with driftwood or bogwood to offer sufficient shade from any harsh lighting. A darker substrate with dark-colored gravel or sand will also foster a dimly lit environment and draw more attention to the blue tetras’ luminous appearance.

Blue Tetra (Boehlkea fredcochui)
Blue Tetra (Boehlkea fredcochui)

Temperature for Blue Tetra

Blue tetras should be kept in water that is at a temperature of around 78°F, although they can withstand temperatures of up to 82°F. In their native tropical habitat, blue tetras live in temperatures ranging from 72°F to 82°.

Water pH for Blue Tetra

Blue tetras water pH should be between 6 and 8.

Water Hardness for Blue Tetra

Blue tetras water hardness should be between 5° and 12° dH.

Blue Tetra Size

On average, blue tetras can grow to become 1.6 inches long, but they have been known to grow up to 2 inches long.

Blue Tetra Tank Size

Blue tetras are an active species and should be kept in a large enough tank to swim around in comfortably. A school of blue tetras will require a tank that holds at least 25 gallons of water. A 50-gallon tank is an ideal option for a group of more than six blue tetras.

Blue Tetra Food & Diet

Because blue tetras are omnivores and natural-born scavengers, they’re typically easy to feed. Blue tetras can be fed high-quality fish flakes or high-quality pellets and will also consume live or frozen brine shrimp and frozen or freeze-dried bloodworms. When feeding bloodworms to blue tetras, they may need to be cut into smaller pieces so that they’re small enough for the tetras to eat. Something to keep in mind when selecting food for blue tetras is: although they’re omnivores, their diet should still include plenty of plant content to provide them with enough nutrients.

Blue Tetra Lifespan

When properly cared for, blue tetras will live for 3 to 4 years. Blue tetras have been known to live up to 6 years in the wild.

Blue Tetra Breeding

When breeding blue tetras, they should be transferred to a smaller, spawning tank filled with soft, acidic water. Blue tetras are egg scatterers; blue tetra eggs should be separated from their parents until they hatch to prevent them from being eaten. A good option is to transfer the blue tetra eggs to a breeding box while they hatch. When hatched, the blue tetra fry can remain in the breeding box to grow, while being fed a diet of infusoria or finely crushed fish flakes until they’re large enough to eat live baby brine shrimp.

Blue Tetra Male and Female

Male blue tetras are usually narrower and bolder in color than female blue tetras, which are plumper and duller than their male counterparts.

Blue Tetra Tank Mates

Blue tetras are a generally peaceful species, although they can exhibit aggression when crowded in a tank with limited room to swim. Lone blue tetras may also behave aggressively without the company of other blue tetras. A good way to prevent aggressive behavior in blue tetras is to make sure that they always have plenty of swimming room and other blue tetras to keep them company.

Blue tetras are most satisfied when surrounded by other blue tetras and should be kept in groups of at least six.

Compatible Tank Mates for Blue Tetra

Blue tetras are most compatible with other small tetras (e.g., Neon Tetras, Ember Tetras, Diamond Tetras, Red-Eye Tetras, and Von Rio tetras); they also typically get along with Corydoras, Rasboras, Mollies, Rainbow Fish, and Platies. A good rule is to keep blue tetras in a tank with non-aggressive fish of the same size and speed so that they don’t run into competition when vying for food.

Incompatible Tank Mates for Blue Tetra

Blue tetras should never share a tank with fish that have long fins. Blue tetras are prone to fin nipping and can mangle fish with long or flowy fins. Guppies, Betas, and Angelfish are examples of fish that should not be kept with blue tetras.

Where can I find Blue Tetra for sale?

Blue tetras are usually found online, where they can be purchased in pairs, or schools of 6 or more. Although they’re not as commonly distributed in the U.S. as other tetras, they may be sold in select local fish shops.

Blue Tetra Price

Blue tetras typically cost between $4-8 (USD) for one pair in the U.S. and can sometimes be found at a discounted price when bought in a group.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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