Tsubakuro Medaka

Tsubakuro Medaka key facts

Care level

Advanced

Lifespan

2-3 years

Size

Up to about 4cm SL

Temperature

18〜28℃

Diet

Prepared medaka food, green water

Lighting

The elongated fins read best from the side, while the black, which does not respond to the background, stands out in a white container. The Medaka Web Encyclopedia recommends outdoor keeping and suggests shading half the container in summer.

Diet & Nutrition

Commercial prepared medaka food is the staple, given in an amount finished within a few minutes. Leftovers decay and foul the water, so adjust the quantity. Green water rich in phytoplankton suits fry rearing.

Water Temperature & Quality

Slightly acidic to slightly alkaline water is considered ideal, and the water drifts toward acidic as keeping continues. Around one water change per week is the guideline, and because sudden shifts in temperature or pH cause stress, acclimatise new fish by floating the bag. FishBase records the wild water chemistry of this species as pH 7.0-8.0 and hardness 9-19 dH.

Tank Mates & Compatibility

Elongated fins are easily damaged by obstructions or crowding, so keep the container uncluttered and the stocking light. A peaceful schooling fish, normally kept as a group of the same variety. One litre of water per fish is the guideline against overcrowding; overstocking causes poor growth, reduced breeding, oxygen shortage and water fouling.

Breeding

The breeder's records give a fixation rate of about 90 per cent for swallow after line breeding, and 50 to 60 per cent for fish expressing both real long fin and swallow. Outdoors the spawning season runs from about April to October, once water reaches 18C or above with 12-13 hours of daylight. For year-round indoor breeding, 25-28C water and over 13 hours of lighting are the guideline. Eggs hatch at a cumulative 250 degree-days, about 10 days at 25C.

Health & Notes

The long fins are easily damaged by obstructions or crowding, so keep the container uncluttered and the stocking light. Only about 50 to 60 per cent of fish express both real long fin and swallow, so selection requires numbers.

About Tsubakuro Medaka

Tsubakuro Medaka is a rare black Hikari-type medaka combining real longfin and swallow traits. Certified as Japan's 38th new variety in 2023, known for its elegant flowing fins.

7 things to know before welcoming a Tsubakuro Medaka

1. 1Suited for Experienced Keepers

   Tsubakuro Medaka combines multiple rare traits, which is why it's considered a variety for experienced keepers. Managing its coloration and body form calls for a solid foundation in basic medaka care. First-time medaka keepers may want to gain experience with a standard variety before taking one on.

2. 2Flowing Fins Are the Main Appeal

   The combination of real longfin and swallow traits produces gracefully flowing fins. Watching them ripple as the fish swims makes for striking viewing, whether observed from above or from the side.

3. 3No Background-Adaptive Color Change

   Tsubakuro Medaka does not exhibit background-adaptive color change, so its coloration stays consistent regardless of the substrate color in the tank. This means the black body color remains stable, though it isn't suited to keeping styles that rely on environmental color shifts.

4. 4Tank Setup Mindful of the Fins

   The long, flowing fins from the longfin and swallow traits can be prone to damage from sharp decorations or coarse substrate. Choosing layout items with rounded edges and avoiding overcrowding with other medaka can help reduce stress on the fins.

5. 5Compact Size, Up to 4cm

   Adults reach a maximum standard length of about 4cm, a compact size that works well in small tanks or biotopes. The fins make the overall silhouette look longer, but the body itself is comparable in size to other medaka varieties.

6. 6A Rewarding Challenge for Breeding

   Because of its rare combination of traits, maintaining consistent characteristics across generations requires attention when breeding. Those who take on breeding can enjoy the process of observing how traits are expressed and selecting accordingly.

7. 7Preparing the Environment Beforehand

   Before bringing one home, it's important to stabilize the tank's water quality and take time with the acclimation process. Since long-finned varieties tend to struggle in strong currents, keeping the water flow gentle helps the fish settle in comfortably.

Frequently asked questions about Tsubakuro Medaka

Q.Can beginners keep Tsubakuro Medaka?

A.Tsubakuro Medaka is considered a variety for experienced keepers. Since it combines several rare traits, it's recommended to gain basic medaka-keeping experience before taking one on.

Q.Is Tsubakuro Medaka subject to CITES?

A.Tsubakuro Medaka is not subject to CITES.

Q.How big does Tsubakuro Medaka grow?

A.Adults reach a maximum standard length of about 4cm, a compact size. The long fins can make the overall length appear somewhat greater visually.

Q.What are the characteristics of Tsubakuro Medaka's fins?

A.It has gracefully flowing fins from the combination of two traits: real longfin and swallow. While this makes for striking viewing as it swims, the fins are delicate, so care should be taken with tank decorations.

Q.Does Tsubakuro Medaka's color change with the tank environment?

A.Since Tsubakuro Medaka does not exhibit background-adaptive color change, its body color does not shift based on the environment, such as substrate color. This means the black coloration stays consistent.

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