Threadfin Rainbowfish: Care, Breeding, Types in Aquarium

A distinctive feature of Threadfin Rainbowfish (Iriatherina Werneri) fish is their spectacular color and lush fins. The front one resembles a sail, and the rear one resembles a lyre (and it is so transparent that you can see the veins). Iriatherina Werneri are peaceful and careful so that the neighbors in the aquarium will not be harmed.

  • Fish size: 4-5 cm.
  • Temperature: 23-28 ° C
  • pH of water: 5.5-7.5
  • Behavior: Peaceful
  • Habitat layer: Top and middle
  • Flock: Staynaya
  • Water type: Fresh
  • Complexity of Care: Average
threadfin rainbowfish iriatherina werneri

Threadfin Rainbowfish appearance and behaviour

These are representatives of the Iris family, so they stand out clearly from other fish:

  • Body: Pink, green, blue shades are visible from different angles (the better the food and conditions around, the richer the colors). Vertical stripes are clearly visible on the body. The shape is elongated, slightly oblong.
  • Head: The front part is slightly pointed due to the original mouth with a large lower lip.
  • Eyes: Light, bright, shiny.

How to tell Threadfin rainbow fish is male or female?

Sex differences are visible by eye:

  • Males are larger and brighter. They have long rays on the anal, caudal and second dorsal fins.
  • Females are slimmer, smaller, paler. There are no rays on the fins.

Are threadfin rainbowfish schooling fish?

The fish is schooling, so at least 5-6 individuals need to be populated into the aquarium, and preferably 10-12. There should be 2-3 females per male so that there are fewer conflicts during the mating season. If Iriaterina lives without relatives, then she will be nailed to other commensurate inhabitants with a peaceful character.

They are active in the water, they move rapidly. Males constantly sort things out, but it does not come to injuries. They only chase each other around the aquarium and measure their fins, whose fins are brighter and longer. Females and fry often swim where they can hide (driftwood, thickets). If they are frightened or notice danger, they quickly hide, regardless of gender.

Threadfin Rainbowfish (Iriatherina Werneri) Habitat

Threadfin Rainbowfish homeland is the southern regions:

  • Australia (rivers Jardine, Edward);
  • Papua New Guinea (rivers Maro, Fly);
  • Indonesia.

Threadfin Rainbowfish swim in slow-flowing rivers and swamps with clean fresh water. They live at a depth of up to 1.5 meters. Their favorite places are driftwood, dense thickets (it is convenient to hide and spawn there).

Threadfin Rainbowfish Care in aquarium

The best option is a species aquarium.  Iriatherina werneri are small, timid, cautious creatures, so it is more difficult for them to compete for food with more agile neighbors.

In a general aquarium, you need to carefully check whether the fish has enough food. If you provide a suitable environment and proper nutrition, then it will live for 3-4 years.

Water requirments for threadfin rainbowfish tank

Prerequisites are purity and oxygen saturation. Aeration and filtration are required up to 2-3 volumes per hour. In addition, the water should always be warm, soft. Accumulation of ammonia and changes in acidity are destructive.

The fish is extremely difficult to tolerate pollution, therefore, once a week, you need to change 25-30% of the water to fresh. Every month it must be completely renewed, and at the same time, the walls of the aquarium, the soil, and the decor elements must be put in order.

Aquarium setup

A playful, mobile flock will need a capacity of 50-70 liters. If Iriaterin is only 5-6, then you can get by with the 25-30 option. You need to put a protective cover or glass on top, because the fish likes to jump out of the water. Lighting should be moderate and diffuse, bright sources are not suitable.

The bottom should be filled with dark crushed gravel. From the scenery, grottoes, caves, ceramic castles are suitable – everything where you can hide. It is desirable that these elements are also dark – this will create a pleasant contrast with the bright inhabitants.

The most important thing is the dense thickets in the water. You can plant Vallisneria, Elodea, Nymphea, Kabomba. It is better to place them along the back and side walls – this way the fish will have room for active swimming, as in their natural environment. Surface plants are also useful pistia, riccia. They will dim the light from the outside.

A compressor with a filter is needed not only for aeration, cleanliness, but also for fun. Streams of water emanate from them, in which Iriaterina love to play.

What to feed threadfin rainbowfish and when?

You need to feed twice a day – in the morning and in the evening. The food must be crushed, otherwise it simply will not fit into Iriaterina’s small mouth. In addition, variety is needed so that the fish receives all the necessary trace elements and retains a bright color.

Suitable diet for Threadfin Rainbowfish (Iriatherina Werneri):

  • Dry food: Unlike live or frozen food, this product is balanced and will definitely not carry a dangerous infection. Tetra Phyll or equivalent can be used.
  • Plants: Boiled lettuce leaves, spinach will do.
  • Protein food: Daphnia, brine shrimp, cyclops, bloodworms are vital.
  • Small pieces of fresh fruits, vegetables (zucchini, cucumbers).

Will threadfin rainbowfish eat my shrimp?

Threadfin Rainbowfish (Iriatherina Werneri) does not eat shrimp and fry. If the food is too large, then the fish may simply remain hungry.

Threadfin Rainbowfish Breeding in aquarium

The mating season lasts from late spring to early summer. At this time, you will need an incubator aquarium with a volume of up to 25-30 liters – an ideal environment for fry.

threadfin rainbowfish breeding in aquarium

The aquarium should have the following conditions:

  • The acidity and temperature of the water are the same as in the parent aquarium.
  • The hardness must be kept at a level of 15-17 dH ° so that as many individuals as possible survive.
  • No neighbors (snails, shrimps), so that the fry will definitely have enough food.

The parent aquarium will need Javanese moss as a spawning substrate. It is advisable to warm up the water there to 26-30 ° C, so that Iriatherina Werneri are more willing to spawn.

The mating season goes like this:

  1. Malek of Iriaterina WernerA sexually mature male occupies an area next to the plant, driving away rivals. The fewer females, the higher the competition, although it will not come to injury and death.
  2. At the sight of a female, the male straightens the rear, anal and front (“sail”) fins. He moves them like a butterfly’s wings, slowly approaching the goal. It’s worth seeing.
  3. If the female is impressed and agrees, then she herself swims up to the chosen one.
  4. Together they retire in dense thickets (in our case, Javanese moss) and spawn.

Females lay several eggs almost daily. If there are shrimps nearby, then you should not be afraid they will not harm anything.

Malek hatch after 7 days. For this reason, it is necessary to transfer the moss to the incubator already 5-6 days after the first spawning, otherwise the fish will appear in the parent aquarium – an imperfect environment for them.

threadfin rainbowfish fry care

Threadfin Rainbowfish fry care

They begin to feed immediately after birth. Fry, like adults, need 2 meals a day.

Starter feed:

  • Infusoria-shoe (Paramecium caudatum) – 70%
  • Philodina rotifers (Philodina acuticornis odiosa) – 30%

The mixture can be diluted at home. It needs to be poured into the incubator for a week until the last fry hatch.

When newborns grow up, they need something bigger. For example, the smallest artificial food:

  • Decapsulated Artemia salina egg – 50%
  • Tetra Phyll – 50%

This mixture must be served in parallel with the starter feed whoever grows up will eat it.

How to look after further:

  1. 10-14 days after the birth of the first fry, all of them can be fed with brine shrimp nauplii.
  2. At 6 weeks, they grow up to 1 centimeter in length, the first sex differences appear. Such individuals can be moved from the incubator to the main tank.
  3. Spawning will begin at 11-12 weeks of age.

Threadfin Rainbowfish mates for aquarium and tanks

Iriatherina Werneri are compatible with everything that is peaceful and preferably of the same size. They do not bother anyone and get along with shrimps, nano-fish, and other representatives of the Rainbows.

It is better not to add large neighbors – they will become a hindrance to active Iriaterians scampering around the entire aquarium. Aggressors who cut off fins (barbs, tetras) are categorically not suitable – they can easily injure or even kill shy little fish.

Threadfin Rainbowfish Varieties and similar species

The entire family of Irises are brothers alike and the best neighbors for Iriaterina. Who is included here:

  • Telmaterina
  • Ladigeza
  • Aterina red
  • Gertrude’s pseudomugil
  • Neon iris
  • Popondetta furkataIris
  • Turquoise
  • Boesman’s iris

There are 2 populations of Iriatherina werneri in nature:


Scales of pearlescent silver shade. Shimmers with all the colors of the rainbow.

New Guinea

The fins are brighter, the body is brown-olive.

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