The Red Eye Tetra Moenkhausia sanctaefilomenae is one of the most readily available tetras in the aquarium hobby. This is one aquarium fish that is now bred extensively in Asia for the hobby. A school of these characins makes for an interesting and lively aquarium.
Although this characin is not as flashy as many of the tetras, it has a charm all its own. The bright red spot over its eyes are an immediate attraction. Its body has a silvery golden sheen with a yellow band on the base of the tail fin, just in front of the of an even broader black band. Of course the common name 'Red-eye Tetra' describes the bright red spot on the upper part of its eye, which makes a bright and rather pronounced contrast to its silvery body. This feature is also described by the common name Lamp Eye Tetra. Other common names, too, are derived from the coloration of this fish, such as Yellow-banded Moenkhausia and Yellowhead Tetra.
These tetras are very durable little fish and will be found in many tanks from the beginner to the more advanced fish keeper. They are very undemanding fish, and they are quite hardy and easy to breed. They are also very active but quite peaceful towards other fish, which makes them a wonderful addition to a community aquarium.
They will be happiest if kept in a school of 5 or more of their own kind. A school will need an aquarium that is at least 15 gallons or larger with plenty of open space for swimming. They do prefer a darker gravel and some plant cover. But even though these are active fish with a good appetite, they will not touch the plants.
The Red Eye Tetra Moenkhausia sanctaefilomenae was described by Steindachner in 1907. They are found in South America, in Paraguay, eastern Bolivia, eastern Peru, and western Brazil. This species is not listed on the IUCN Red List. Other common names they are known by include Lamp Eye Tetra, Yellow-banded Moenkhausia, Red Eyed Tetra, Redeye Tetra, yellow back moenkhausia, Yellowhead Tetra, and Yellowhead Characin.
In the wild they prefers to inhabit clear water rivers but can some times be found in living in the thick vegetation of the murky Amazon.They swim in schools and feed on worms, crustaceans, and insects. Aquarium fish for the hobby are now bred extensively in Asia.
Scientific Name: Moenkhausia sanctaefilomenae
Social Grouping: Groups
IUCN Red List: NE - Not Evaluated or not listed
The Red Eye Tetra has a full-bodied typical tetra shape. This fish will reach about 2 3/4 inches (7 cm) in length and has a lifespan of about 3 - 5 years in the aquarium. It has a silvery colored body with a rather golden cast, and transparent fins. Their most distinguishing characteristics include a yellow band on the base of the caudal fin, just in front of the of the black area, thus the most usual common name 'Yellow-banded Moenkhausia'. Another common name, 'Red-eyed Tetra', describes the bright red spot on the upper part of its eye.
Size of fish - inches: 2.8 inches (7.01 cm)
Lifespan: 5 years - They have a life span of about 3 - 5 years.
Fish Keeping Difficulty
The Red Eye Tetra is a hardy fish that is good for the beginner fish keeper. Because of the great changes in water conditions between the wet and dry seasons in its natural habitat, this fish is not very fussy when it comes to water conditions and can tolerate a wide range within reason.
Aquarium Hardiness: Very Hardy
Aquarist Experience Level: Beginner
Foods and Feeding
Since they are omnivorous the Red Eye Tetra will generally eat all kinds of live, fresh, and flake foods. To keep a good balance give them a high quality flake food everyday. Feed brine shrimp (either live or frozen) or blood worms as a treat. Vegetables should be offered regularly to get the most out of its color and appearance. Spinach is a great choice for this fish. This tetra prefers to eat multiple times a day. Offer only what they can consume in 3 minutes or less with multiple feedings per day.
Diet Type: Omnivore
Flake Food: Yes
Tablet Pellet: Yes
Live foods (fishes, shrimps, worms): Some of Diet
Vegetable Food: Some of Diet
Meaty Food: Some of Diet
Feeding Frequency: Several feedings per day
The Red Eye Tetra is easy to care for provided the water is kept clean. Aquariums are closed systems and regardless on size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the water hardness increases due to evaporation. To combat these ever changing conditions water should be replaced on a regular basis, especially if the tank is densely stocked. At least 25 - 50% of the tank water should be replaced every other week.
Water Changes: Bi-weekly
These fish are fairly hardy and a school of 5 - 6 will do best in a 15 gallon aquarium or larger. These fish do not prefer fast moving currents, so make sure to angle the filters to avoid disturbing these fish. In nature these fish come from regions with dense forests that let little light through, so the tank should also be dimly lit.
The aquarium should be heavily planted around the sides and back and have plenty of open water for swimming in the front. A few hiding places would be appreciated. Woodwork and floating plants will make them feel comfortable. Like many of the tetras, adding aquarium safe peat to the filter will simulate the black water conditions that they prefer. Adding a couple handfuls of dry leaves will also give these fish a natural feeling. It is best to use a river sand for the substrate.
Minimum Tank Size: 15 gal (57 L) - This fish appreciates a large open swimming area.
Suitable for Nano Tank: Yes
Substrate Type: Any
Lighting Needs: Moderate - normal lighting
Temperature: 72.0 to 82.0° F (22.2 to 27.8° C)
Breeding Temperature: 82.0° F - The breeding tank should have soft and acidic with a pH 5.5 - 6.5 and a temperature between 80 - 84° F.
Range ph: 5.5-8.5
Hardness Range: 2 - 30 dGH
Water Movement: Moderate
Water Region: All - These fish will swim in all areas of the aquarium.
The Red Eye Tetras are generally good community fish but will be happiest if kept in a school of 5 or more of its own kind. This tetra can intimidate sedate fish because they can be very boisterous, so keep them with active tank mates. Good tank mates are other tetras, rainbowfish, barbs, larger rasboras and danios. Most peaceful bottom dwellers will do well too. These tetras are also known for their fin nipping, but this can be discouraged when they are kept in a school.
Same species - conspecifics: Yes - This fish should be kept in at least a small school, with 5 or more suggested.
Peaceful fish (): Safe
Semi-Aggressive (): Threat
Aggressive (): Threat
Large Semi-Aggressive (): Threat
Large Aggressive, Predatory (): Threat
Slow Swimmers & Eaters (): Safe
Shrimps, Crabs, Snails: Safe - not aggressive
Sex: Sexual differences
The only truly distinguishing feature to differentiate the sexes is that a mature female has a more rounded stomach.
Breeding / Reproduction
The Red Eye Tetra are egg layers. They are easy to breed and will freely spawn in schools or in pairs. When they spawn they lock fins, then while clasped they perform a type of roll-over process in the vegetation. Thus the female releases about a dozen eggs at time and the male fertilizes them. Because of this spawning behavior, the Red Eye Tetra is one tetra that must not have too dense a spawning vegetation.
Most successful way to spawn these fish is in groups of 12 with 6 males and 6 females. Feed this group small live foods and nature should take over and spawning will begin. A separate breeding tank will help to get the best number of fry. Keep the tank dimly lit with clumps of spawning mops or java moss so the female has a place to deposit the eggs. A layer of mesh also works as long as the spaces are wide enough for the eggs to pass through and small enough to keep the parents out. The water should be soft and acidic with a pH 5.5 - 6.5 and have a temperature of 80 - 84° F. A small air powered sponge filter is all that is really need for filtration. Filtering the water through aquarium safe peat is a good choice.
Once a successful spawn has been achieved remove the parents. Eggs will hatch with in 24 - 36 hours with fry becoming free swimming 3 - 4 days later. For the first few days feed the fry infusoria type foods until they can feed on microworm or brine shrimp nauplii. Fry are light sensitive during the early stages and require it as dark as possible. Also see Breeding Freshwater Fish: Characins for a general description and see Fish Food for Fry for information about types of foods for raising the young.
Ease of Breeding: Easy
The Red Eye Tetra is very hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won't have to deal with health problems or disease. Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.
A good thing about the Ornate Tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Flame Tetra the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.
As with most fish they are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Red Eye Tetra is readily available in pet stores and online, and is moderately priced.
j.divall - 2015-04-19 Hello, Friday i got 6 red cardinal's, yesterday i could only count 5, and today 4! I have just witness the red eye tetra's chase and eat 1, is this normal behavior?
Clarice Brough - 2015-04-20 Well tetra's can get nippy, and bigger fish often go after smaller fish. You usually want to have each type of tetra in a good sized school, and have plenty of hiding places with plants and decor.
AngieB33 - 2014-12-31 Just added three red eye tetras to my 20 gallon long tank. Long time occupants are three Julii corys, two peppered corys, one large emerald cory and two otocinclus. Also adopted a tiny Julii when I got the tetras because it was in a tank with only two female guppies that wouldn't play like corys. They have all adapted well to a well established tank with very active moving water. Would like to add two more tetras, because they really like to be in a group of five or more, but don't want to overpopulate the tank. So far there is no problem keeping water clean and clear. Using CaribSea Eco-Complete substrate, which is phenomenal for the corys. Always use an oversized filter along with a sponge filter and extra air stone. Some live and some plastic plants. Appreciate opinions on adding the additional two tetras.
Clarice Brough - 2014-12-31 They are small fish so won't add much load, and because your tank is so well established I bet it will work out fine. And yes, the tetras like a group:)
Anonymous - 2013-04-30 I have a few red eye tetras in a 20 gallon long aquarium and they are lively. They can be a bit aggressive at times with smaller fish, and don't even think about putting them in with any type of small invertebrates, such as ghost or cherry shrimp, since they will devour them. Other than that, red eyes are an entertaining fish that are reasonably hardy, and in groups large enough for them to school, can be quite striking to look at.
Collin - 2012-10-14 I've had 3 red-eyes for over 3 years now and one of them has a small bloat in front of the anal fin, does anyone know what this is?
Clarice Brough - 2012-10-14 Hard to say for sure, but there are several possibilities. It could be constipation, possibly a pregnant female storing eggs, a swim bladder problem, or an internal parasite. Constipation would look like a swollen tummy - the area right behind the ventral fins and right in front of the anal fin. A pregnant female also has a swollen area infront of the anal fin, so that could be more likely if your fish still has a healthy appetite.