Tamasaba

This site has a rule it repeats: a deep-bodied fancy goldfish is a fish for indoors or a mild climate, and does not belong outdoors through a hard winter.

The tamasaba is the notable exception, and the reason for it is traceable.

Identification

A deep body carrying a single tail. That is the look, and it is the reverse of the wakin — one is a long body with a doubled tail, the other a round body with a single one. Between them they show that body shape and tail count are separate traits that usually, but not always, travel together.

The tail is undivided, and it varies. It runs from a short crucian-type tail to a long streaming one like a comet’s, and from fish to fish and line to line. The name tells the story: tamasaba is tama, ball, for the round body, and saba, mackerel, for the tail of the older sabao type it was selected from. The sabao is the less round of the two, and the tamasaba the rounder.

A back that rises behind the head, close to a ryukin’s profile, with a tall dorsal fin. A tamasaba is often taken for a ryukin with a single tail, and in shape it is close to one.

Red and white is the classic colouring. Solid red, yellow and calico fish are also bred, and the best have clean white fins.

Ryukin, fantail or tamasaba?

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  Ryukin

  A hump behind the head

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  Fantail

  A smooth egg shape

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  Tamasaba

  A ryukin’s back, one tail

Three deep-bodied goldfish side by side: a ryukin with the hump behind its head ringed, a fantail with its smooth back ringed, and a tamasaba with its single long tail ringed.

1. Ryukin. The back climbs sharply behind the head before the dorsal fin, on a deeper body. In a young fish the hump is slight, so judge body depth too: the British standard asks for about 80% of body length in a ryukin and 65% in a fantail.
2. Fantail. The body rises in one smooth egg shape with no hump, over a double tail.
3. Tamasaba. A back that rises behind the head like a ryukin’s, with a full dorsal fin, but a single undivided tail, which in the photograph is a long one.

Photographs: Ryukin, Lerdsuwa, CC BY-SA 3.0; Fantail, ProjectManhattan, CC BY-SA 3.0; Tamasaba, Desaix83, after Ghasem1122, CC BY-SA 3.0. Rings added.

How it develops

No timetable has been published for the tamasaba, so there is no table of ages here. What the sources do say is short. The breed was selected over generations for a rounder body and a longer tail, the tail varies from short to long, and the back from steep to gently sloped, so a young fish is a prediction in the way every fancy is: goldfish genetics explains why.

The line decides more than the juvenile does. A single-tailed ryukin can look the same at any age, and a young tamasaba cannot be told from one by its tail. Where it was bred is the question to ask.

Why this fancy is reported cold-hardy

Worth setting out properly, because “a fancy that overwinters outdoors” sounds like a claim to be sceptical of, and the history is the reason to take it seriously, as long as it is called a report and not a measurement.

The tamasaba was developed in the Chūetsu district of Niigata Prefecture, in northern Japan, largely by koi keepers — people whose fish are expected to come through the winter. The story is that it came from a ryukin crossed with the single-tailed Shōnai goldfish, a cold-hardy type from the neighbouring region that is no longer available, and Japanese sources say it was bred from the start to swim with koi. It was almost lost in the war, and was bred back from the survivors.

So the hardiness is not a property of the shape. It is thought to have arrived from the other side of the parentage, which is how goldfish genetics says traits behave: they recombine, and there is no reason a body and a temperature tolerance have to travel together.

And one thing the ancestry did not change. The body is still a ryukin’s. Nothing about the tamasaba’s digestion has been published, and what reports exist call it less prone to disease than a ryukin, but the sensible assumption is that a deep body brings the usual care for buoyancy, and floating upside down is worth knowing about.

Aquarium requirements

100 litres minimum for the first fish and more comfortably, the same floor as any fancy of its size — the tank size guide has the arithmetic. Reports of its adult size disagree, from about 18 to 20 cm including the tail to well over 30 cm, so plan for the large end.

Or a pond, which is where it is kept in Japan. It is often raised in outdoor ponds and viewed from above, and a UK importer describes it as pond-hardy all year. Goldfish ponds covers what one needs, and a tamasaba can use the same one a comet would, including through the winter that a pond through the year sets out.

Steady water, and not hot. It is reported hardy in the cold, so the number that matters is the warm end: no goldfish wants to sit above the mid-twenties for long, and the temperature guide is clear that heat is the harder problem for all of them.

Gentle to moderate flow. It swims better than its shape suggests but it is not a comet, and a long single tail still catches on sharp decor.

Personality and behaviour

Agile and surprisingly quick. Japanese sources describe a tamasaba that swims with the agility of a wakin despite its ryukin shape, as a fish bred to share a pond with koi should, and it competes at feeding time in a way a ranchu cannot. That changes the tankmate arithmetic in both directions: it keeps up with single-tails, and it will outcompete the slower fancies.

That makes it one of the few fish that sits comfortably in either group, and the compatibility checker will settle any specific pairing.

Feeding

A fancy’s regime, not a single-tail’s, as a precaution. In Japan it is fed the same food as the koi it shares water with, and nothing about its feeding has been published beyond that. The body is a ryukin’s, so soak dry food, feed sinking pellets, keep portions small and include vegetables, as overfeeding goldfish and sinking versus floating set out for round-bodied breeds.

And feed to the temperature, in a pond. As the water cools the fish digests more slowly whatever its reported tolerance, so the seasonal taper in feeding through the seasons applies in full. Cold hardiness means it is reported to survive the winter well, not that it should be eating through it.

Common health considerations

Buoyancy trouble is possible, as in any deep-bodied fish, and nothing breed-specific has been published about it.

Fin damage, because a long single tail on a fish that turns hard meets sharp decor. Torn fins covers it.

Otherwise reported robust. No wen, no altered eyes, no bubble sacs, and accounts that call it less prone to disease than a ryukin. What to watch is what signs of a healthy goldfish lists.

What goes wrong, in order

What you see	What it usually is	Where to go
Floating or struggling to stay down	The deep body, usually after eating	Floating upside down
A tear in the tail	Sharp decor, met at speed	Torn fins
Slower fancies thinning	Outcompeted at feeding	Tankmates
Sluggish through a mild winter	Normal, and not a problem to fix	A pond through the year
Bloating after a cold snap and a meal	Fed while too cold to digest	Feeding through the seasons

Overwintering one

The practical payoff, and the part worth getting right because it is the reason to own the fish.

The pond has to be a proper pond. Depth, volume and a surface that can be kept open matter far more than the breed does. Building a goldfish pond covers depth and siting, and a shallow ornamental basin is not made suitable by stocking it with a hardy fish.

Keep a hole in the ice, which is the one non-negotiable of a frozen pond. Gases have to exchange; a sealed surface over a pond full of decomposing material is how fish are lost in winter, and it has nothing to do with cold. The seasonal routine in a pond through the year is the whole of what to do and none of it changes for this breed.

Stop feeding as the water cools, on the same schedule as any pond fish. This is where reported cold tolerance is most often misread: a fish can survive winter well, and a fish fed through winter does not.

Let it cool gradually. The reported hardiness is to a season, not to a shock. A fish moved from a heated indoor tank into a cold pond in November has been given a different problem from the one it was bred for.

Choosing one

• Look for a single tail on a deep body, and treat it as the look and not as proof. A single-tailed ryukin can look the same.
• Ask where it was bred, because the reported hardiness is a property of the line and not of the name, and a fish raised warm has not shown it.
• Check the tail is undamaged, since its sweep is the feature.
• Expect to buy from a specialist, usually a koi importer. A tamasaba in a general shop tank is more likely a ryukin with a single tail.
• And know where specialists are found, which is its own exercise and is set out in finding a goldfish no shop stocks.

Is a tamasaba right for you?

Yes, if you want a fancy-shaped goldfish for an outdoor pond and have been told repeatedly that there is no such thing. This is the one that is reported to manage it, and it is the reason to seek it out rather than settle for keeping a ryukin indoors.

No, if you wanted the fancy look without the fancy feeding. The body is a ryukin’s and the precautions come with it, and reported cold tolerance changes none of that.

History and origin

The tamasaba was bred in modern times by koi keepers in the Chūetsu district of Niigata Prefecture, from what the story gives as a ryukin crossed with the single-tailed Shōnai goldfish. It was selected for a rounder body and a longer tail than the older sabao, it was meant from the start to swim with koi, and it nearly disappeared in the war before it was bred back. It is still mostly a koi farmer’s fish, and it travels to the West with koi shipments.

What makes it worth a page beyond its rarity is what it demonstrates. The domestication story is usually told as a list of traits accumulating — a doubled tail here, a shortened body there, a hood on top. The tamasaba is the same process run for a different purpose: not a new ornament, but an existing ornament made to cope with a Niigata winter and a koi pond.

That is a breeder solving a climate problem rather than chasing a standard, and it is a good example of goldfish keeping as agriculture rather than as decoration.