Serpae Tetra 101: Care, Tank Mates, Breeding & More

Serpae Tetras are a wonderful freshwater fish that have a strong foothold in the aquarium scene. We had our first experience keeping one around five years ago, and have been a fan of them ever since.

Here’s why:

This species is not only beautiful, but they’re easy to keep. This makes them very beginner-friendly, or perfect for an aquarist who’s looking for something low-maintenance.

This guide will teach you the basics of Serpae Tetra care. We’ll cover things like tank mates, lifespan, diet, size, breeding, and more!

Species Summary

Colorful and incredibly active, the Serpae Tetra is a fish that will add some vibrancy to your tank. These fish have become quite popular among the aquarist community due to their playful attitudes and stunning good looks.

Scientifically known as Hyphessobrycon eques, these fish go by many names. They’re often referred to as Jewel Tetra or Callistus Tetra in the aquarium trade. Whatever you choose to call them, there’s no denying their beauty.

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One Serpae Tetra swimming near the surface near feeding time

Serpae Tetras are endemic to the Amazon River basin in Argentina, Brazil, Paraguay, Peru, and Bolivia.

Typically, they can be found in slow-moving backwaters. In the murky waters of their natural habitat, they spend most of their time taking shelter from predators below. However, in a captive aquarium, they are the stars of the show.


The average Serpae Tetra lifespan in captivity is between 5 and 7 years. For this family of fish, that life expectancy is pretty standard.

This can be impacted by the usual factors. Poor water conditions, a lackluster environment, and a less-than-stellar diet can shorten the life of the Serpae Tetra dramatically.

Author Note: It’s possible for them to exceed this expected lifespan as well. Some owners who’ve given them fantastic care have seen them surpass the 7-year mark!


Serpae Tetras are part of the Characin family. Thus, they have that familiar profile as some other types of tetra species. They’re relatively flat but have a tall frame and a trapezoidal shape.

The most visually striking aspect of the Serpae Tetra is their color. Most specimens take on a reddish-brown color. Base coloration can vary quite a bit with this species.

Some are more olive-brown while others take on a fiery scarlet hue. Either way, there’s one thing that all of these fish have in common. Their scales have a shiny finish that’s shimmers in the light. It creates a jewel-like luster that you can’t miss.

Beyond their base color, the Serpae Tetra has several distinct patterns on their bodies. The most noticeable is the black comma-shaped spot on their sides. Located just behind their gills, this spot can fluctuate in vibrancy. Some specimens even lose it altogether as they get older.

A close up view of the Serpae Tetra

On the top of the fish, you’ll notice a large square-shaped dorsal fin covered in dark black. There may be some slight redness on the base of the fin. If you look very closely, many fish also have white edges on their dorsal fin.

This unique color pattern continues on the anal. However, rather than being covered in black, it’s predominantly red with black tips. A light smattering of white on the tips is pretty common as well, giving these fish an almost hand-drawn appearance in your tank.

The interesting thing about Serpae Tetras is that their colors can change multiple times throughout their lives. For the most part, the base colors remain unchanged. However, the vibrancy will improve or degrade based on their diet and environment.

There isn’t a ton of distinct differences between males and females. Usually, females are less vibrant than their male counterparts. They can also be a bit plumper ( especially true around breeding time).


The typical Serpae Tetra size when fully-grown is around 1.75 inches in length. These are not very large fish!

It is possible for larger specimens to reach a full 2 inches, but this is pretty rare (especially in captivity). If you purchase your fish from a disreputable seller it’s far less likely that they’ll reach their maximum size.

Serpae Tetra Care

Serpae Tetra care is usually considered to be one of the easier tasks in the freshwater fishkeeping space. The water conditions they need are quite manageable and they require a straightforward diet. And even though they’re highly active, they will rarely show signs of aggression.

Of course, that doesn’t mean that you can ignore care guidelines. Like any fish, Serpae Tetras have some set conditions that you need to provide. Doing so will help the fish reach their full potential while reducing the risk of any health concerns.

Tank Size

Thanks to their small size, Serpae Tetras don’t need the massive tanks that most tropical fish require. Some aquarists have seen great success raising small groups in tanks as small as 10 gallons.

However, we recommend starting with a tank size of 20 gallons for the best results.

While they might be small, Serpae Tetras are big swimmers. They need plenty of space to explore. A larger 20-gallon tank provides that much-appreciated extra room.

Plus, it allows you to keep a larger group together, which is always preferred (more on this later).

Water Parameters

As we mentioned earlier, Serpae Tetra can be found in slow-moving backwaters. Usually, those habitats are calm, dark, and murky. They’re filled with blackwater, giving the fish plenty of opportunities to hide from predators.

Replicating that type of environment is crucial if you want to keep your fish healthy. You don’t have to go as far as creating true black water with a murky tint, but you can do your part to mimic the rest of the water conditions.

The natural environment of a Serpae Tetra is warm, soft, and slightly acidic. We recommend setting up your tank ahead of time and giving it plenty of time to cycle through. These fish are quite sensitive to major fluctuations in water conditions.

Giving your tank ample time to settle will ensure that your fish can get introduced to the new habitat without any issues. Here are some base parameter guidelines to follow for Serpae Tetras:

  • Water temperature: 72°F to 79°F
  • pH levels: 5 to 7.8
  • Water hardness: 5 to 25 dGH

Setting Up Their Tank

Providing the right underwater landscape is just as important as closely monitoring water conditions. The key to keeping any fish species happy is to create a cozy habitat that closely resembles their environment in the wild.

The Amazon River basin is teeming with life. While you can’t always see what’s going on above the surface due to the murkier waters, those bodies of water are very dense with vegetation.

We recommend starting out with a dark sandy substrate.

A black or dark gray sand replicates muddy pond and river beds. Usually, bodies of water in the Amazon basin have a fine layer of decaying plant life at the bottom. The dark sand will mimic that.

Hyphessobrycon eques swimming along the substrate

Next, incorporate plenty of live plants throughout the tank.

Plants are very important for Serpae Tetras. Not only do they often snack on the plants, but they provide shelter. In the wild, these fish are usually seen congregating around tree roots.

They’ll do the same in your tank. Plants like Java Moss and Myriophyllum are good choices. Those plants offer great shelter while still letting the fish move through the leaves.

Arrange these plants in dense clusters around the edges of the tank. You don’t want to fill the middle of the aquarium with too many plants.

This is because Serpae Tetras need some room to swim. Filling the tank with too many plants may make that difficult.

Mix and match the plants with other forms of natural decor. Things like driftwood and rock formations are all good items that provide shelter.

Moving onto equipment, Serpae Tetras don’t have a ton of strict requirements when it comes to filtration. Any standard canister filtration system or hang-on-back unit will suffice. As long as it can effectively cycle the tank, it should do just fine.

The only thing to be wary of is the force of the return tube. Serpae Tetras prefer slow-moving waters, so make sure that it’s not too powerful. If it’s on the stronger side, you can place a plant or decorative item in front of the tube to break up the stream.

Author Note: Another important thing to consider is lighting. The murky waters of the Amazon basin don’t allow too much light in, so Serpae Tetras prefer things to be more subdued.

Luckily, the fish aren’t too picky with that regard as long as you have plenty of plants to block out light throughout the day.

Potential For Disease

We’re happy to report that Serpae Tetras don’t have any species-specific ailments that you have to watch out for. That said, these fish are susceptible to all the common freshwater ailments.

These include things like Ich, fungal infections, and skin flukes. You can easily avoid many common health conditions by simply staying on top of water conditions. Most diseases are a direct result of stress and poor living conditions.

With consistent monitoring and regular water changes, you should have no problems keeping your Serpae Tetras healthy.

Food & Diet

Serpae Tetras are omnivores by nature. In the wild, they typically eat plant matter and insect larvae floating on the surface of the water. In captivity, they are happy with just about anything you provide.

You can choose to feed your fish a regular diet of high-quality flakes or pellets. This can serve as the foundation of their diet.

It’s a good idea to supplement with some protein-rich foods as well (this will balance things out). The occasional snack of bloodworms, brine shrimp, and other live or frozen proteins are good as well.

Behavior & Temperament

For the most part, Serpae Tetras are peaceful. They are fast-moving fish that get along with several other fish species.

As we mentioned earlier, these are community fish that thrive in larger groups. When paired together, they’ll spend a lot of time exploring the tank.

Two Serpae Tetras swimming quickly around the aquarium

Larger groups help make the fish feel more confident. They behave differently and will spend less time hiding when there are other Serpae Tetras around.

Typically, they stick to the middle and bottom of the aquarium. They’ll occasionally swim to the surface (usually during feeding time).

These fish do exhibit some unique swimming patterns. Rather than swimming elegantly throughout the habitat, they will swim in a jerky rhythm. They’ll swim in short bursts before resting and starting again.

This can prove to be problematic in some scenarios. Serpae Tetras have been known to show some slight aggression towards slow-moving with long fins. They may nip the fins of Angelfish or Bettas, so exercise caution.

Serpae Tetra Tank Mates

The best tank mates for Serpae Tetras are other Serpae Tetras. We recommend keeping a group of 5 to 7. These fish may fight amongst one another, but it’s usually no major cause for concern.

They tend to develop a pecking order within the group and will show some slight aggression towards those that are weaker. Keep an eye on the group and take out any aggressors that cause harm or make it hard for other fish to eat.

Aside from other Serpae Tetras, these fish are compatible with other fast-moving peaceful fish. It’s best to avoid slow fish that could be targeted for fin nipping. You should also avoid larger aggressive species that may try and eat your Serpae Tetras.

Here are some good tank mates to consider:

Author Note: While some aquarists have had success keeping freshwater aquarium snails as tank mates with Serpae Tetras, we don’t recommend it. It doesn’t work out the vast majority of the time.


Breeding Serpae Tetras is an easy process. Though, it must be done in a separate tank. This species shows no parental instincts at all and will be a danger to your baby fish almost immediately.

Create a separate breeding tank that’s decorated similarly to that of the primary tank. Incorporate lots of plants and consider using a breeding mop. Serpae Tetras are egg-layers that will scatter their eggs throughout the environment.

Thick vegetation and breeding mops will catch the eggs and keep them protected. As for water conditions, you can keep things on the softer side. The pH balance should be around 6.0. Warmer waters up to 80 degrees may be used to trigger the breeder process.

Before you move your group of adult Serpae Tetras into the breeding tank, condition them with some protein-rich snacks.

Live and frozen food will help to move the spawning process along. Once your females get plumper, you’ll know it’s time to start breeding.

Males will chase the females around, causing her to scatter eggs throughout the tank. The males will then fertilize those eggs. Hundreds of eggs can be laid at once.

You should keep an eye on the process and remove the adults immediately after they are done. They tend to try and eat eggs very quickly.

After about 2 days, the eggs will hatch. The baby fry will eat their egg sacs and grow a bit before swimmingly freely. At that point, you can provide baby brine shrimp and infusoria for food.

Keep your baby fish in the separate tank until they are big enough to eat dry flake food and fend for themselves.

Wrapping Up

Serpae Tetras are a fantastic species to keep in a freshwater tank. Plain and simple.

Honestly. they could be one of our favorite Tetras at this point (and that’s saying something). With their beauty and low-maintenance nature, they’re a good fit for just about everyone.

Give them a shot! You’ll be happy you did.

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