I heard it is not so often that a puffer spawn in a captivity. They spawned after about a half year since I got them. There is summary of what happened in the spawning season in this page. I'm happy if this would be help who intended to breeding dwarf puffer. They keep spawning even now, I will add the progress to this page.


I had kept six (two males and four females) dwarf puffers since April, 1999. When I brought them in my tank, they seemed to be just like kids, were one or one and half centimeter long. At first time, they all were in the Tank 1. Tank 1 was not densely planted then, had a few plants and two 10x10cm stones in it. When I saw courtship behavior first was about five months later (Sep. 12, 1999). A male has following a female after and snuggling to her. I saw such activities every day after the day. One day, two males did fights very hard. I thought if one might kills the other, so I bought a new tank (Tank 2) and did isolate three (a male and two females) of them to the new tank. Soon after the day, I saw spawning and then found a egg in the Tank 1. A few days after, I found eggs in the Tank 2. They seemed to get into spawning season at the same time.

Courtship Behavior and Spawning

I saw a courtship behavior at a day a half year after I started keeping them.

Courtship Behavior

  • Male snuggling to female and kissing her body with chasing her. Female swims slowly as usual, but male swims with wiggling, that is a sequence of a quick and a little step.
  • In case female goes away from male, Male attacks her hard and occasionally bites her.
  • In case female does not goes away, male swims beside female and female gradually goes into a narrow space such as a corner of a tank or a shade of plants. Maybe female is searching a good place to spawn.
  • While they doing this behavior, the male attacks another fellows (without regard to sex) when he found them. But the male does not attack Otocinclus.
  • In case a male and two females are kept in the same tank, male do the courtship behavior with each females, i.e. they three does not make a pair.
  • In the tank mentioned above, when a male and a female doing the courtship behavior, the other female keeps hiding and still behind something such as plants.  


  • Once female decides a place to spawn, male nestles closely up to the female. Both male and female shakes each body little by little for about 5 or 10 seconds, that is spawning and releasing sperm.
  • In the case of mine, almost all spawning was done in/under a mass of Willow moss. It was done rarely by a stem under a big leaf of Anubias Nana.
  • Male drives out female when spawning done.

Other Points

  • While spawning season, the courtship behavior (and maybe spawning) would be done almost every day.
  • The courtship behavior and spawning must be done at evening.
  • The courtship behavior was done after layout change of a tank and after completely tank cleaning.

Male's Behaviors in Spawning Season

This section is described that the behavior and the appearance of male dwarf puffer in spawning season except courtship behavior and spawning mentioned above. Both male and female does something had never ever seen in spawning season.

Changing Appearance

  • Brown vertical line appears on the belly.
  • Body shape get pretty sharp and less round than of female.
  • Patterns of back are almost always fading (as light brown) as compared with females yellow back.
  • Top and bottom edge of tail fin get more yellow than before.
  • Patterns on the side get together and to make a line.

Doing Serious Fight With Another Male 

I saw such a fight once, then I worried that if the two males would being together as they are, they would doing fight to death, so I moved the one male and two bride candidates to the other tank. Because of this, I'm not sure whether they do fights to death or not if they were in a same tank for a long period in a spawning season. But I can say it should be considered that separating males in the season. The fight is as follows:

Two males started pecking each other (that is a little fight as usual). A few second later, they two males transformed flatly as if his body was pressed from the side. (this photo had been taken when he started such a transformation and would fight with the other one on the other side of the partition. this was taken at another day.) They ran on the same circle about five rounds. Then they clashed. One bit left side of belly of the other very hard and they gone down behind a mass of willow moss. A few seconds later, they got out of the moss and gone away. After that, I looked at left side of belly of one was bitten, there is something like a wound or wrinkle.

I set a breeding box in the tank and put the one was bitten into the box. Next day I set a partition in the tank and separated each one male and two females to half tank. At last, I set up a new tank and moved tree of them to the tank.

Photo: Two males are going to start such a fight.


Eating Less Amount of Food

Males does not jump to food and eats less amount of food than females.

Doing Patrol

Until evening, both males and females swims peacefully. From evening to night, males will starts patrolling around a tank (especially around a mass of willow moss) and drives out females very hard from there. Females did often hide behind a leaf of plants.

Keeping Strong Wariness

Every time I get close to the tank, Males do react (get away) extremely. On the other hand, Females doesn't react such.

Place to Spawn

In case of mine, almost all spawning was done in/under a mass of Willow moss(Fontinalis antipyretica). It was done rarely by a stem under a big leaf of Anubias Nana. I think the place they will spawn is :

  • a narrow space (that is not enclosed by something hard could hurt their body)
  • and where difficult to be found from outside

In my puffer tanks, willow moss is rounded softly and has just been placed between stone, filter pipe and back wall of the tank. It's convenient to pick the eggs up and maybe it would be a good hiding place for fry. But willow moss would be dying gradually because of lack of light. 


New egg is about 1mm, transparent, has no adhesion and has a little white part. A small number of eggs I found were wind eggs (were cloudy white).

New eggs - almost transparent After a day -  get light brawn and eyes(?) After two to three days - expands light brawn part  After four days - almost light brown

Hatch and Larvae

In case of mine, eggs hatch for about 5 days (27°C). At the time this photo was taken, the fry keep still with such a pose for about 20 seconds or so, then got off the egg, swam toward surface and sank to bottom.

 Newly hatched fry is :

  • tiny (about 1 - 1.5mm),
  • like a drosophila which wrenched blade and foot,
  • basically, transparent, around head and base of tail got orange-colored,
  • has yolk-sac,
  • almost being quiet, swims toward the surface when water flow came, stop swimming at the surface, sank to the bottom as if he did die, and being quiet again at the bottom.

Fry (Within a Week)

For about four days, they start to swim. They are almost still yet,  but sometime run through the bottom of tank and hover nearby willow moss. Appearance is exactly different when they hatched. At first, eyes can be seen clearly, black dot is in the center of gold or light brown eyes. And They can already moves eyes like adult dwarfs does. Outline of body would be as fish. Fins can be seen too. Maybe fins can already moves because they can hover. Brownish color of body gone as compared with when they hatched. At this time, they doesn't eat yet.

For about five to six days, they grows about 3mm. Time to be still would be shorten, they swims around almost all time (except sleeping time). Sometimes they eats white tiny (2mm long) creatures like a earthworm. They chases baby brine shrimps,  but doesn't eat yet.

In my tank, two fry died on a heater. Maybe they were burned by heater when they sat on it. Heater cover may not work due to the size of fry. In my case, I moved the heater to just below exit of water from filter.

Fry (a Week After)

Fry a week after hatching start feeding baby brine shrimps. How much they fed could be seen by looking at  the belly of them. It will turn orange in color when they got fullness. This photo is fry ten days after hatching.

Fry a few weeks after hatching can kill fry a few days after hatching. (I'm not sure if they 'ate' them or not.)

Fry (a Month After)

Fry will be the same body shape as adult  when about a month after hatching. The spots on back would be clear. But the back doesn't get yellow yet and belly doesn't get perfect white yet (orange color of brine shrimp in the stomach could be seen through.). They would be able to feed a smaller bloodworms and a tiny cut of tubifex worms.

Fry in this age, when they were hungry, can kill fry a few weeks after hatching by biting off. I'm not sure if they 'ate' them or not. Separating bigger fry and smaller fry is necessary. 

Fry Foods

Fry of dwarf puffer would feed brine shrimp for a week after hatching. They feed only moving food for a few weeks. They would feed (small) frozen bloodworms for a month. 


A Group of Paramecium

Copyright © Wim van Egmond

Infusoria, in general,  has been used to feed to very tiny fry of fishes such as a fry of betta. 'Infusoria' is a general term for many kind of microorganisms, such as paramecia, euglena, desmids, rotifers and so on. I cultured infusoria using a piece of cabbage and a few drops of milk, but finally didn't feed it to the fry because I heard on Pufferfish mailing list that many kind of infusoria can kill young fish. And the other reason I avoid to feed them is that It can pollute tank water. Actually, that's dirty and smelling bad, of course!,  that's just rotten cabbage. But I also head Paramecia can be fed to sensitive fish. It can be cultured easily as follows:

Thanks: I quoted the following descriptions from the message posted by Manuela in ONEList Pufferfish mailing list

You could get paramecia if you take a bit of hay and let it rot in water (rain water, no tap water because of the chlorine); after a few days or weeks there will be tiny white spots which move - these are the paramecia. You can feed them with a few drops of milk and keep the culutre so for years without breeding other microorganisms by accident.

Water Insects

Another option of very small foods are water insects such as water flea(daphnia), Cyclops and Grindal worms. Cyclops is used as fry food generally, can be caught at a pond and be cultured, but in case of mine, they raised naturally in the tank. I'm not sure whether that is a water problem or not. But I think they came from Willow moss that I put in the tank. I had found them in the tank once, but they disappeared later. I'm not sure, but think the fry ate them up.


Copyright © Wim van Egmond

Liquid Fry Food

You may also use liquid fry food. I couldn't use it because can't found ones here in Japan.

Newly Hatched Brine Shrimp

Fry would feed newly hatched brine shrimp for a week after hatching. 

Tubifex worms (cut to two or three mm long)

Fry would feed a small piece of tubifex worms for about two weeks after hatching.

Frozen Bloodworms (about 5mm long)

Fry would feed bloodworms for about a month after hatching.

Tanks for Dwarf Puffer

In Here, My tanks keeping dwarf puffers in are displayed. No! As you can see, this is never a kind of "My proud tanks!!" :) I'm just willing to show you what kind of tanks my puffers bred in there.

At the first time, all six dwarf puffers had been kept in the Tank 1. Two 10x10cm stones, Binchotan (Japanese charcoals has effect of cleaning water) and a few plants (Anubias nana, Limnophila sessiliflora...) had been used as decollations then. The photo was taken recently. A mass of willow moss is laid behind stone near the center back.

Tank 1
Tank Tomofuji TIAX (W30cmxH30cmxD20cm 17 litters)
Filter undergravel filter and corner overflow filter? (filter media: wool mat, BIOMIX and sand)
Heater IC mini auto heater (70W, fixed at 26ºC±1ºC)
Lighting 8W (turned on 10 hours per a day)
Substrate Oiso sand
Water Condition freshwater, 26-31ºC pH7.0-7.2 GH8ºdH
Water Change once at a week (dechlorinated tap water)
Plants Willow moss, Anubius Nana, Limnophila sessiliflora, Mayaka?, Hinjimo?, xxx
Fish Dwarf puffers (a male and a female), an Otocinclus

A half year later, I moved three of them (a male and two females) to the new tank, Tank 2.

Tank 2
Tank Kotobuki Debut (W35cmxH30cmxD21cm 21litters)
Filter undergravel filter and corner overflow filter? (filter media: wool mat and sand)
Heater auto heater (100W, fixed at  26ºC±1ºC)
Lighting 13W (turned on 10 hours per a day)
Substrate Osio sand
Water Condition freshwater, 26-27ºC pH7.0-7.2 GH8ºdH
Water Change once at a week (dechlorinated tap water)
Plants Willow moss, Anubius Nana, xxx,yyy,zzz
Fish Dwarf Puffer (a male and a female), two Otocinclus

When first fry hatched, I set up the Tank 3.

Tank 3 (Fry tank)
Tank Tetra Glass Aquarium GB-30 (W30㎝xH20㎝xD20㎝ 11 litters)
Filter Sponge filter
Heater auto heater (60W, 15-35ºC±1ºC, setting at 27ºC)

11W (turned on 10 hours per a day)

Substrate none
Water Condition freshwater, 27ºC pH7.0-7.2 GH8ºdH
Water Change once per 1-3 days (2 litter)
Plants a little willow moss
Fish 30 dwarf puffer fry, a few pond snails (for cleaning)

Sorry for the insufficient explainations above. The only one English word which I know for introducing these web sites is "GREAT!!".

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