Big List of 5 Blue Tetra Fish Ideas for Your Aquarium

Tetras are among the most favorite fish for many aquarists for a simple reason, their mesmerizing colors. They can be colored in red, black, yellow, blue, and even a rainbow!

With their relative ease-of-care, they can be the perfect choice for beginners who still have a lot to learn.

As a little help, I thought I should introduce various tetra species in multiple articles based on their color. In this article, I’ll review the best blue tetra fish that contrast well inside any tank.

Let’s get into the list;


Suggested Equipment For Your Blue Tetra Aquarium

Here Are 5 Blue Tetra Fish For Your Aquarium

Finding a few blue tetras is pretty easy; however, we’ve managed to narrow it down to a few of the best.

Here they are;

1. Cochu’s Blue Tetras (Boehlkea Fredcochui)

  • Care level: moderate
  • Size: 2 inches
  • Temperature range: 71 – 80 °F
  • PH range: 6 – 7.5
  • Social behavior: schooling fish
  • Tank size: 20-gallon

I can’t start a list of blue Tetras without mentioning the breed with “blue” in its name. Cochu’s blue tetra, aka Blue King, is among the most common tetra types in the US.

Unlike most tetras, Cochu’s tetras don’t have a wide color variation. Their bodies can range from deep blue and bright pink according to their health condition.

The peripheries of their bodies tend to be mostly transparent, leaving the center with deeply saturated scales. However, all their fins are entirely transparent.

Thankfully, Cochu’s tetras aren’t demanding at all. A rookie aquarist can keep them without significant problems. Due to their schooling nature, you’ll have to keep them in groups of six.

To account for their activeness, the tank should be big enough with medium vegetation. It’s better to restrict the plants to the tank’s sides to leave a large middle area for free swimming.

When it comes to breeding, things might be a little tough for first-timers. Cochu’s tetras tend to scatter their eggs all over the fine vegetation. It’s crucial to maintain perfect water conditions to stimulate hatching properly.

2. Blue Tetras (Knodus Borki)

  • Care level: easy
  • Size: 2 inches
  • Temperature range: 72 – 78 °F
  • PH range: 5.5 – 7
  • Social behavior: schooling fish
  • Tank size: 20-gallon

As you might already know, common names aren’t always accurate. This breed is also named “Blue Tetra,” but it’s completely different from Cochu’s tetras. For the sake of clarity, I’ll use its scientific name, Knodus.

Unlike Cochu’s tetras, Knoduses have brighter and more saturated blue scales scattered all over their bodies. Their fins are often transparent, but they might have light blue margins. On a dark background, their fins look like blobs of color freely floating around them.

When preparing their tank, it’s essential to know that Knoduses are a bit lazy. Therefore, it’s better to cram the tank with dense vegetation that diffuses the light.

Adding some twisted branches toward the tank’s base would simulate their Amazonian origin. You can also add some tannins-rich peat into the filter to darken the water and complete the jungly feel.

To satisfy their schooling nature, you should place at least eight tetras together. It’d be a good idea to avoid placing smaller species in the same tank because Knoduses might nip their fins.

Feeding Knoduses is as convenient as other tetras. They can depend on nutritious pellets as the main diet. But incorporating Bloodworms, Daphnia, brine shrimp, and Spirulina should get them in their best form.

3. Neon Tetras (Paracheirodon Innesi)

Neon Tetra

  • Care level: easy
  • Size: up to 1.5 inches
  • Temperature range: 69 – 80 °F
  • PH range: 6.0 – 6.5
  • Social behavior: schooling fish
  • Tank size: 15-gallon

From here on out, I’ll review species that have hints of other colors on their bodies rather than being strictly blue. For my first recommendation in this category, I couldn’t find anything better than Neon tetras.

We can confidently agree that Neons are the most popular tetras worldwide. Aquarists love them for their bright blue/red bodies.

Typically, the blue shade dominates from the eyes to the tail fins. The red shade, however, starts around the middle while being limited to the lower half of the body.

Interestingly, some Neons might intentionally dim their colors in times of fear or inactivity. That’s great news for fish nerds who like to stare at their aquarium day in and day out.

Their wide popularity isn’t only attributed to their bright colors, though. Neons are arguably the easiest to take care of between other tetras.

They’ll eat anything small enough to get into their mouths. Giving treats of Bloodworms, brine shrimps, Daphnias, and Tubifex should keep them healthy.

You can diversify by placing other species together with Neons. They’re generally peaceful as long as you keep them socialized in schools of 6-8 tetras.

4. Cardinal Tetras (Paracheirodon Axelrodi)

Cardinal Tetras (Paracheirodon Axelrodi)

  • Care level: easy to moderate
  • Size: 2 inches
  • Temperature range: 72 – 82 °F
  • PH range: 5.3 – 7.8
  • Social behavior: schooling fish
  • Tank size: 20-gallon

You can still get the same brilliant colors with the astonishingly-similar Cardinal tetras if you couldn’t find Neon tetras.

With a brief look, a rookie aquarist might not be able to tell Cardinals and Neons apart. But if you look close, you can distinguish them by the red shade. In Cardinals, the red stripe extends throughout the full body. In Neons, red only colors the posterior half.

Aside from this, Cardinals are nearly identical to Neons. They can be fed anything with a suitable size. But they also appreciate occasional treats of Daphnia.

When preparing their tank, bear in mind their South American origin. They’ll need fairly dense vegetation to serve as hideouts during the night. They can also feed off the small organisms living there, achieving more diet variety.

However, breeding them might be somewhat challenging for inexperienced aquarists. You have to keep tabs on the water condition to promptly correct anything that goes off.

Inside community tanks, Cardinals should be peaceful around smaller species. But they might turn a bit aggressive when kept in schools smaller than four tetras.

5. Red-Blue Colombian Tetras (Hyphessobrycon Columbianus)

Red-Blue Colombian Tetras

  • Care level: easy to moderate
  • Size: 2 inches
  • Temperature range: 72 – 82°F
  • PH range: 6 – 7.5
  • Social behavior: schooling fish
  • Tank size: 30-gallon

Although tetras often have streamlined bodies, you can still find species with plump configuration toward the front. Red-Blue Colombian tetras are the perfect examples.

The body of a Colombian tetra is primarily colored in silver-grey. Toward the top, a blue shade starts to intensify until it becomes a well-pronounced stripe.

Fins, on the other hand, are predominantly colored in red, hence the name “Red-Blue.” Just like Neons, Colombian tetras are capable of dimming their fin colors during rest.

Initially, Colombian tetras are peaceful around other tetras as well as smaller species. However, they have the highest tendency to develop aggressive behavior if their demands aren’t met. That’s why it’s incredibly important to keep them in schools bigger than eight tetras.

Feeding them shouldn’t be hard for any aquarist, regardless of the experience. They happily accept flakes, freeze-dried, and small live foods.

Unfortunately, Colombian tetras aren’t readily found in the US. You’ll need to find an exotic fish breeder to add them to your tank.

To Sum Up Our Blue Tetra Fish Ideas

Blue tetras are among the best species to add contrast to a green tank. If you want strictly-blue species, you should like Cochu’s and Knodus Blue Tetras. If you’re searching for other color variations, consider Neon, Cardinal, and Red-Blue Columbian Tetras.

Generally speaking, these five species should be easy to handle even for beginner aquarists. The most important thing is the school size. It’s better to avoid going smaller than groups of 6 to prevent aggression and health deterioration.

However, for Cochu’s and Cardinal tetras, breeding might require experience and special care. So consider other tetras if you’re a first-timer.

Looking For More Colorful Tetra Ideas Check Out These Articles:

List Blue Tetra Fish Ideas for Your Aquarium

Jack Dempsey
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