breeding part II
  • 06.07. - 25 L tank
    This evening I removed moss from my 54 L breeders tank and put it into my small 25 L tank.
    There is no gravel in the tank only the swimming moss which I will remove after 8 days when hopefully all fry are hatched. I'm using a sponge filter.
    I have been doing only weekly waterchanges in my breeders tank for two months now. Waterchanges are done with rainwater, KH 2° and pH 7.0 - 7.5.
    They haven't got much bbs during the last weeks, only Cyclop Eeze, crushed dried Daphnia and some crushed flakes. Temperature was 30° C. permanently.

    Since a few weeks my Threadfin breeders live together with 5 couples of Pseudomugil gertrudae. The gertrudae are approx. one year old and I guess the've already reached sexual maturaty. This means there might be eggs of both in the moss.

    After hatching I'll move the fry immediately to the outdoor tub. This has to be done extremely carefully because werneri fry very often die very fast by injuries caused by a net. This is an experience I made by my last werneri breeding. I will just move a simple water glass along the surface to catch them.

  • 07.07. - 25 L tank
    One evening later I found the first single tiny fish. I'm a little bit spoiled from last time when I found 25 little fry the next morning. So I have to be patient and wait a few days.
    One thing's for sure - I can't put those 4 mm fish together with the juveniles in the outdoor tub. I'll to put my bigger fry from the tub to their siblings in the 112 L tank.

    08.07. - 25 L tank
    Nothing happened, just one tiny fish. I will call him Robinson Crusoe. It's obviously not so easy to get a big number of eggs and fry. The daily water changes and lots of artemia feeding I did last time must have made sense. If I won't see any positive results within 4 days, I'll put the moss back to the breeders tank.

  • 54 liter breeding tank, 50% waterchange, 30° C., KH 3°, pH 7.5
    I started doing waterchanges at least the other day and feeding lots of brine shrimp. This is what I think was the reason for getting a big number of eggs and fry last time. I'm not really in a hurry but September will be the last month where efficient breeding will be possible for me. I'm still dreaming of a heavily planted 150 X 60 X 60 cm tank (540 L) only for I. werneri and P. gertrudae. That would be a nice project starting October ;-)
  • outdoor tub,  30° C
    I moved all larger fry to the 112 L tank now which means the outdoor tub is prepared for some (hopefully hatching;-) new fry.

4 weeks old

4 weeks old


I haven't measured pH and KH continiously in my breeders tank. I used ion exchanger water last time and rainwater now, I didn't feed brine shrimp for a while. Last time I mixed water from an ion exchanger with tap water , so I had always control over KH and pH by the mixing ratio and I could keep temperatur warm by using warm tap water. Now the rainwater that I collect in an underground cistern has also 2° KH but pH is between 7.5 and 8.0. I don't get pH down to 6.5 by adding BIO CO2. Only a professional CO2 system as I use it in my 240 L show tank can do this job ! I did only weekly water changes during the last weeks.

My conclusion after 2 breeding attempts ......

* sex ratio 1:2 for the breeders
* pH 6.5 - 7.0, KH 2°-3°, temperature 30-32° C.
* water changes at least every other day (25%)
* feeding brine shrimp and Cyclop Eeze 4 times a day
* A breeding tank that's at least 60 cm long with a lot of moss

This is no guarantee for success but the probability is increasing extremely !

  • 09.07. - 25 L tank, 30% waterchange, KH 3°, pH 7.0, 30° C.
    Today I found 3 more fry which I moved immediately to the outdoor tub.
  • 54 liter breeding tank, 25% waterchange, KH 2°, pH 7.0, 30° C.
    I'm feeding brine shrimp and Cyclop Eeze 4-5 times a day and the Threadfins look very
    nice. The males show phantastic colour while mating. Maybe the gertrudae eat the eggs in the moss. The werneri have never been interested in the moss but the gertrudae are searching for food in the moss very often.

  • 10.07. - 25 L tank, 20% waterchange, KH 3°, pH 7.5, 30° C.
    Today I moved 13 more little fry to the outdoor tub so there are 17 little fish in total.
  • 54 L breeding tank, 25% waterchange, KH 2°, pH 7.0, 30° C.
    There is nothing special to report, my Threadfins look great and I think they are spawning permanently. Feeding brine shrimp 4 times a day shows results. I will remove moss one more and see what's gonna happen. If there are only 20 little fish again it might actually be that the gertrudae eat eggs. Then I will put 5 adult I. werneri (2 male, 3 female) to the 25 L tank with the moss.

  • 12.07. - 54 L breeding tank, 25% waterchange, KH 3°, pH 7.0, 29° C.
    Nothing spectacular to report, everything is fine in this tank. I installed a new BIO CO2 bottle two days ago which started production yesterday evening. This will hopefully keep pH slightly below 7.0 in combination with 2° KH.
  • 25 L tank, waterchange 25%, KH 3°, pH 7.5, 30° C.
    I found 10 more fry today, in total it's not a big number but it's not the desaster I expected after the first 2 days ;-)
    I don't get pH down in this tank but I don't worry about that because all fry move to the outdoor tub the same day. Adding CO2 doesn't make sense because I won#t find the right dose at all and risk ill or dead fry. That's not worth it.

  • 13.07. - 25 L tank,
    7 more little fish moved to the outdoor tub.
    I ordered to pH meters for my 54 l + 25 L tanks so using drops will have an end and I'll have pH values available permanently.

  • 14.07. - 54 L breeding tank, 25% waterchange, 2° KH, pH 6.8, 30° C.
  • 25 L tank - 25% waterchange, KH 2°, pH 7.0, 30° C.
    5 little more fish that moved to the outdoor tub. I will remove the moss tomorrow and substitute it by new moss from my breeding tank.
  • outdoor tub, 30% waterchange, 30-34° C.
    Summer is back....temperature heas been increasing  from 14° C. up to 35° C. within 2 days which means I have at least 30° C. in the tub now. It's incredible,you can see already a big difference in colour and size of the I.werneri fry after 2 days.

  • 17.07. - 112 L juveniles tank
    Today I found fry in this tank. The oldest fish in this tank hatched on 25.05.2007, which means they are not even two months old. So I moved already 13 little fish to the outdoor tub today and some more will follow. In the 112 L I've also been doing small 10-30 % waterchanges 3-5 times a week and fed a lot of newly hatched brine shrimp
  • outdoor tub
    Two days ago I put some moss from my breeders tank into a net that's hanging in the outdoor tub and what a surprise... the first fry hatched last night.

I think I will stop this breeding diary now because it's becoming a never ending story
;-))).  I found out different methods of breeding Iriatherina werneri and it depends on the situation which method I'll use in the future. If you've any questions regarding breeding these wonderful little fish, please feel free to contact me.




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