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SnailsForktail Blue-Eye Rainbowfish Care & Info
Looking to bring some life into your shrimp tank or community aquarium? Despite its small size, the forktail blue-eye rainbowfish (yes, we know it's a bit of a mouthful!) has a lot to offer. Colorful, peaceful, and suitable for smaller aquariums, this might be just the fish you're looking for.
Below, let's have a look at everything you need to know about the forktail blue-eye rainbowfish (Pseudomugil furcatus), including how to identify it, where it's from and how to care for it in the aquarium.
| Scientific name | Pseudomugil furcatus |
| Common names | Forktail blue-eye rainbowfish, forktail rainbowfish, furcata rainbowfish |
| Difficulty level | Easy |
| Origin | Papua New Guinea |
Table of Contents
Forktail blue-eye rainbowfish appearance & natural habitat
Appearance
The forktail blue-eye rainbowfish looks pretty typical for members of its genus, which also includes the popular spotted blue-eye (Pseudomugil gertrudae) and red neon blue eye (P. luminatus). It's easy to identify Pseudomugil rainbowfish: they're small, have oversized, colorful fins, and their pectoral fins stick up in a sort of permanent cheering position.
The forktail blue-eye in particular can be recognized by its yellow-tipped fins and - who would have guessed - its forked tail. The species has shimmering, bright blue eyes. I noticed one German author refer to them as aquatic butterflies, and I'm inclined to agree with that assessment!
Rainbowfish display striking sexual dimorphism (visual differences between males and females). As often happens in nature, the ladies are relatively unassuming in terms of looks: mostly greyish with some yellow accents.
The boys are a different story. Tasked with impressing the opposite sex with intricate fin displays and sparring sessions, they have longer fins. Their yellow coloration extends to the belly and chin.
Did you know? Although this species was originally placed in the genus Pseudomugil, it was subsequently moved around a good bit by celebrated ichthyologist and rainbowfish expert Gerald R. Allen (to Popondetta and Popondichthys), before eventually ending up right back where it started.
Natural habitat
It might come as a surprise given this species is quite popular in aquaculture, but the forktail blue-eye rainbowfish actually has a very small natural range. It's found in Papua New Guinea, where it was first collected in 1953 during expeditions to New Guinea for the American Museum of Natural History. The species was officially described in 1955.
In the wild, Pseudomugil furcatus inhabits a select few rainforest streams in the Northern and Milne Bay Provinces of the island. This is a habitat characterized by its slow currents and abundant (aquatic) plant growth. In the rainy season, these streams can swell a good bit. In the dry season, on the other hand, they can turn into barely connected pools.
The IUCN Red List notes there is not enough information available to determine if forktail blue-eye rainbowfish are threatened in the wild. It adds that it probably is, though, with logging operations affecting its habitat. Oil palm plantations and gold mining likely cause water pollution.
Did you know? The forktail blue-eye appears to be relatively easy to breed on a commercial scale. The fish you'll find in your local aquarium store are not wild-caught.
Setting up a forktail blue-eye rainbowfish aquarium
Requirements
Although this species is considered a nano fish, it's also active and a quick swimmer, so it can't be kept in the smallest tanks. A 15-20 gallon long aquarium is a good place to start for a small to medium-sized shoal.
When setting up an aquarium for your forktail blue-eye rainbowfish, keep in mind that this species hails from densely vegetated waters. They like something similar in the aquarium, so it's a good idea to include plenty of (floating) aquarium plants.
Heavily planting the aquarium also comes in handy if you'd like to keep yours with shrimp, as it gives young shrimp a place to hide and forage until they're large enough to avoid being eaten by the rainbowfish.
Water parameters
Although forktail blue-eye rainbowfish are relatively flexible when it comes to water composition, it's important to make sure the aquarium is properly cycled and has had some time to age before you introduce them, as they can be on the sensitive side.
Ammonia and nitrite levels should always stay at 0. Nitrates should ideally be <10, which can be maintained through weekly small water changes.
pH: 7-8
Temperature: 75-82 °F
Hardness: 5-11°
Tankmates
Forktail blue-eye rainbowfish are a shoaling species that relies on strength in numbers to feel safe. To see yours in their full glory, you should get at least 5, preferably 10 or more.
We know it's tempting to get only males, which are much nicer to look at, but it's best to keep at least equal numbers of males and females (or more females than males). If they're healthy, the boys will color up nicely and spend much of their time sparring and showing off for the ladies. Quite a sight to see!
As for other tankmates, these rainbowfish make a great addition to a peaceful community tank. Any inoffensive fish and invertebrates that prefer similar water values should work well. You can try neon and cardinal tetras, rasboras, Cory catfish, kuhli loaches, and much more.
If you'd like to keep your forktails with shrimp, that's possible, although we recommend against mixing them with more expensive dwarf shrimp varieties. After all, they're omnivores that won't say no to an easy meal of baby shrimp! Still, with plenty of plant cover, your shrimp colony should be able to thrive alongside them.
As a little bonus: some sources note the peacock goby (Tateurndina ocellicauda) as a particularly suitable tankmate for the forktail blue-eye rainbowfish. This is not surprising, as the first forktail blue-eyes were actually collected alongside this species.
They hail from the same waters, are peaceful and get along well with Pseudomugil rainbows. Great for a super colorful Papua New Guinea biotope aquarium!
Forktail blue-eye rainbowfish diet
Wild forktail blue-eye rainbowfish are omnivores. They feed on a variety of plankton and small invertebrates in the wild, and should receive something similar in the aquarium.
A formulated fish food should work fine, but do keep in mind that these rainbowfish are tiny. Micropellets should work well, as will very small frozen and live foods like daphnia or baby brine shrimp.
Breeding forktail blue-eye rainbowfish
These rainbowfish aren't very long-lived (2-3 years), but this shouldn't be a problem if you have a mix of healthy males and females. They're pretty prolific and you should be able to breed them in your aquarium without too much trouble.
To get your forktail blue-eye rainbowfish to breed, you can raise the temperature in your tank to around 82 °F. Try feeding some nutritious live food as well. Place a spawning mop or some stem plants in the aquarium for the eggs to be deposited on.
If you want more fry to survive, separate the eggs after the fish finish spawning, as they'll eat them if they get the chance. Place the mop with the eggs in a container of aquarium water with an air stone, performing daily small water changes.
The eggs should hatch after around three weeks. You can feed the fry using powdered foods, newly hatched brine shrimp and similar until they're large enough to be moved to the main aquarium.
If you're not feeling the idea of having to set up a second container for the fry, you can try to see whether they make it in the main aquarium. Again, the parents will eat them if they can, but hobbyists do report relatively good results when floating Java moss or long-rooted floaters are added to protect the babies and give them a place to forage.
Buying forktail blue-eye rainbowfish
The forktail blue-eye rainbowfish is a relatively popular species in the aquarium hobby, which means you likely won't have too much trouble finding them. If your local aquarium store doesn't have any in stock, they may be able to order some in for you.
You can also opt to buy online. The Shrimp Farm carries forktail blue-eye rainbowfish and ships them right to your doorstep!
