Zdeněk Dočekal - Aquarium fish breeding

Continuation of the first part of the interview.

As I look around the aquariums full of healthy and beautifully colored fish, I can't help but focus my questions on the issue of breeding.

Do you faceany any major problems with breeding?
For example, after 30 years, my angelfish eggs have started to fade.

And the water parameters are the same?
That's just it. It seems to be the same. I don't want to bring conspiracies into this, but it's not just happening to me. It's happening to other people elsewhere, but not everywhere.

So there are problems. Sometimes you breed cardinal tetras, but with the next generation it may not be the same. But maybe the next one is good again. It's not like it works this year and it will work again next year. Sometimes it's good, then maybe worse or completely bad. I've learned that in these 40 years.

Simply, you never know. When you change breeding fish, it's always a question mark.

But that's breeding, so it's better to choose good fish, not to leave just some leftovers, and then breed with it.

So there are breeding problems. In the beginning, when I started, I read a book and it said that the water must be such and such, so I ran through the forests and measured the water in the springs. It's beautiful in the forest again (laughs).

We have a famous spring here (in the Kutná Hora region)…
I know about it. There is also a famous one between Jihlava and Pelhřimov.
I'm just thinking of going there to put the fish in this development water.
But that applies to all breeders. Sometimes it works, sometimes it doesn't.

But it is interesting that one says "now I will breed these fish" and it hardly succeeds. Then you take others that I didn't even want, and they thrive…

When you start pushing the saw, it doesn't work, when you're relaxed, then yes. When violence is used, it usually doesn't go well.

And what do you enjoy most about aquariums?
Especially when it's going well? Yes, because you know what? What can entertain a workaholic? When the work is going well!

I could retire. Well, yes, but then I would watch TV? So I have it running, I have the shops. There are younger people everywhere than me. Only the suppliers and I are the same age.

And by visiting each other, that I come on Thursdays, I come on Fridays, then they bring fish again, we chat... Then I drive through the shops, I'm among people. I'm a community type.

Until I was 50, it was a side job. I used to go to the factory. And at 50 I couldn't do it anymore. I said to myself, I have to end something. So I quit my job at the factory. I kept the fish.

I have another income, a pension, so that's good. You calm down that it is so. You have this deceptive security that at least something will come. When things weren't going well before, bills kept coming, more was being debited from the account than was coming in. Those are nerves.

And that's where you start making mistakes.

But when you're relaxed, then it works, it's not about getting rich, but it's a trade that you can make a living from.

And that I can buy what I want. For drinks, for food, I go wherever I want. That I can't go to Kuwait every year? What would I do there? I would stress about what's happening here with the fish…

I totally understand…
This is ideal, these two-day events. Maybe leaving on Friday and arriving on Sunday, that's fine.
I choose these weekends. And there are enough of them in a year. (laughs) Some people work all year round, then they go on vacation for fourteen days.

I would like to talk about the water again, as such.

What has worked best for you to prepare it? 
I have reverse osmosis for tetra species. For neons you can also get water from nature, but this is easier. But if it doesn't work then, I might take a canister and go.

So with the tetra species, Hemigrammus rhodostomus, I do it with reverse osmosis, which I then harden as needed.

And how do you best adjust the pH?
It's either chemical, but I do it by adding water from nature to this water, which has maybe 2 to 4μS. I know a water where the pH is 5, acidic water. Then I pour that in and it keeps the pH 5 of the natural water.

I make it maybe 20μS for neons. So I add enough to the zero water to have 20μS and the pH there is 5. And when I need other fish, I go to another spring where the pH is 6.

In natural water, the pH doesn't travel that much. If you do it chemically, or aerate it, the pH usually goes up.

When I mix it with natural water, it is a fact that there are more white eggs, but the fish are not crooked. It keeps the values I want before I start feeding. Then the water also goes down.

So that's how it is, the starting point is reverse osmosis. I've tried it this way and that. And then adjusting with natural water.

Cardinal tetras need acidic water, Congo tetras - acidic water, but Hemigrammus rhodostomus need a higher pH. When it is very acidic, there are many males and it sells poorly.

And the rhodostomus, the females are beautiful. There is a big difference, it sells better. So the tank is then ready for sale sooner.

That's interesting. Several aquarists actually say about different species that it sometimes happens to them that they are all females or all males.
With rhodostomus it doesn't matter, because they are not sold in pairs, but with cichlids, they want them in pairs. They either feed them or trade them when someone has males and someone has females.

When the Pelvicachromis taeniatus nigeria red started x-years ago, the females were more colorful than the male. They still wanted them in pairs. Well, and it happened to me too. It happened to me that I had more females. Maybe 80 females and 20 males out of a hundred fish. So I stopped doing that too.

It is said that temperature actually plays a role, but there are probably more factors.
pH certainly too. I've tried that. With a higher pH they spawn better, but then there are more females. Also with Congo tetras, when the pH is 6.2, they spawn a lot, but then there are many females. So I then gave it for feeding.

The same with rainbow fish, I do it in tap water. So with rainbow fish, I sometimes have females left over, but it's not as bad as with Congo tetras, for example. So now I know that I make pH 5 there and that's it. The willingness to spawn is not so great. But they spawn, and then it's almost half males and females. Or sometimes it even happened to me that there were more males, which sold better, some only wanted males. They are more colorful. The female is really just such a white one.