Time consuming larvae development

[Thomas Beu]

For the past two years I have successfully been breeding Parosphromenus filamentosus and P. Nagyi.

Especially the development of the Larvae of P. Nagyi takes a lot of time. Adult fish appear earliest 10-12 months after hatching.
I feed them almost daily, the nutrition consists of freshly bred Artemia, small black mosquito larvae and micro-worms.

I change 50% of the water in three day intervals in the beginning, the intervals change to once a week later on.

Water-parameters: 20-40 µS, 5.5-6.5 pH

What are your experiences on this topic?

[Patrick Guhmann]

I think it is very important to discuss the groth rate of fish. Because every one wants to know if he raises the fish well. I have only little experience with Parosphromenus (see #215). In the past I searched for this topic (groth rate of Apistogramma, Dicrossus and Poecilocharax) in the literature and www, but I found only very poor information. Perhaps some breeders can share their data with us. So we can create a table with groth in cm and time in weeks/months for several species.

[Peter Finke]

That’s an interesting topic and there is much information on it. But I do not know a place where it is gathered in a comprehensive way.
All experts agree that the development of young Parosphromenusneeds more time than with many other fish. Less than half a year until reaching the adult stadium is never experienced. I know of licorice gouramis bred by commercial breeders (who normally don’t breed these fish at all) that were only seven months and quite big and ready for spawning, but they were fed very intensively by Tubifex and in many cases didn’t live long later on. Many experts speak of (and experience themselves) three quarters of a year as the least. The pioneer Dr. Walther Foersch wrote of an interval of four or more weeks in the middle of the growing phase. In my opinion this depends on the circumstances; good, but diversified feeding and frequent water-change shortens the time they need for growing and may even let fall away that interval.
Therefore the time-span that Beutho tells us is to be seen as quite normal. That’s much compared with many other fish. But it does not indicate wrong treatment or false aquarist methods.
On the other hand, the fish we receive via the trade are mostly young fish of the last spawning period. Often, they arrive not yet in the adult stadium but still need two to four months in good care. That might indicate a somewhat faster development in nature. But I am not sure. The young fish of this year are the parent fish of next year’s spawning period. Therefore, a big difference to our aquarium observations is not to be seen. But we observe another thing, too: Some individuals of the same spawn grow faster, others less fast. This is a natural adaption, nature’s precaution against fate.
In general one can say: Parosphromenus are slow growers.

[Thomas Beu]

Thanks Patrick and Peter for your acknowledgements. I also assume that Paros in general are slow developers. The juvenile phase forms a considerable part of the whole life-span. So patience is a basic requirement for breeders. By the way, some visitors mentioned that my juvenile Paros were grey and boring coloured fish. Indeed, colours only appear in adult males. These are seldom seen because they often hide in the breeding-caves. But in my opinion, it is fun to watch the juvenile-development. Even very small ones perform territorial behavior and have some “micro-fights”. Furthermore, young Paros are fearless and very curious. I like them!
PS. My P. nagyi-youngsters (Cherating, F2) will be ready for distribution soon (Location: Frankfurt)

[Peter Finke]

Dear Beutho, I am attending a conference in Frankfurt 22th July (Oeko-house, near station Frankfurt west). I very much would take some (two young pairs, 4 ex.) of your young Cherating, for my fish have died from Oodinium. This might be done either before (12 – 13) or after (17.30 – 18.30) the conference.
Could we arrange that somehow? And have some small-talk?

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