Tank cleaning/water changes in a tank with fry

[Stefanie Rick]

Good Morning!

There are some very interesting threads about water changes here in this forum. I now have a more special question, not concerning water changes in general but in a tank with many young fry:

– How do you change water without exhausting some of the fry by using a hose?
– How do you thin out the cover of water plants without removing fry from the tank?

I have used something similar to Helene’s method up to now (relatively often set up a new tank) but in a slightly different way: I don’t remove the fry (there are too many tiny ones which wouldn’t be caught) but the adults and put them into a freshly set up tank. Then I leave the fry in the old tank until they have grown up to a size they can be easily caught. (I can be sure then that there are no newborn fry because I removed the parents). I put the fry in a new tank and empty the old one completely.

But I now have a tank with rubrimontis parents and small fry, and a tank with Betta hendra and their fry. Both tanks need a thorough cleaning, the plant cover must be thinned out and so on. Especially in the Betta tank there are so many fry swimming everywhere, sitting between the roots of the plant cover and so on – I would kill lots of them if I removed plants or exhausted water with a hose.

What do you do in these cases, what are your methods?

[helene schoubye]

I think that you should not underestimate the fry’s ability to take flight when ‘something’ is going on. In my experience putting down a hose and sucking out water is not likely to bring out any fry. If you hold it just beneath the plant cover and above the bottom – and make some ‘noise’ then that part is possible.
Also with plant cover, if you make some movements, stir a little, the fry will swim away. You might lift up the plant to mid of the tank and keep shaking it a bit – it will eventually make the fry seek other hidingplaces. And then take the plant into a small container with little bit of water and observe it well for any fry. They are easier to see then also.

If you want to empty out the whole tank it is a lot more complicated, with the bottom debrie and all that. But I still think the method is possible, making certain the fry can see and feel that they should get away, then suck a bit out careful.
Also if you take out all decorations and plants and leave the tank to settle its much more easy to then see how many fry and where they are. I do admit its a process that could take hours.

I always use quite a thin hose, that is also important in order to control things.

The fry which unfortunately gets ‘hosed’ up normally doesnt suffer if they are small.

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