changing water with fry?

I have a 2ft 60litre tank and a 1ft 10litre tank.

I recently discovered some Dwarf Neon Rainbowfish fry (six or seven) and currently only have..

• 3 remaining fry in my small tank (three or four died)
• 1 fry (probably a week or two old) in my large tank (along with other adults)

I've been worried about shocking the fry in the small tank so I've been taking this approach once a week..

1. Take ~16 litres out of the 2ft tank.
2. Add ~16 litres tap water of similar temperature treated with Seachem Prime.
3. Let it circulate a bit.
4. Take ~half the water out the 10litre tank.
5. Replace ~half the water in the 10litre tank with water I've removed from the 2ft tank.
6. Top up the 2ft tank with water from the top treated with Seachem Prime.

Now bear in mind that the 1ft 10litre tank doesn't JUST have the fry in it - it also has some substrate (find and large gravel), half the snail population of the world as well as some hornwart and random moss.

At its' peak - the small tank had six fry in it. I'm down to three. One tiny one from about a week ago. One that I think is probably two or three weeks old and one that is a month or two old now. In fact I'm wondering if the bigger one shouldn't be put in the big tank again..

My questions after this convoluted long ramble:

1. Am I completely wrong? Should I be doing a ~10% water change once a day with fresh tap water for the small tank? That is what I've read on some other sites.
2. Should I move this guy back into the bigger tank? (you can see biggie quite clearly in the first pic but in the second pic he/she got shy and turned away. medium fish is on the left and microscopic fish is on the top right in the second pic)

 

Well done on the fry. Two things that I have learned, while reading up on Kutubu fry, is that rainbow fry is sencitive to water temp fluctuations. Meaning wc water should be the same temp as grow out tanks water. For the first 2 weeks it is best not to do any wc but then you will need to do them quute frequintly. All said this is when your talking of 100 fry in a tank. Your bio load is not that big, even considering the snails in the tank. I will only do a 10% wc weekly for now and when the fry double in size you can start doing it 2 x a week as feeding will increase

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My standard for WC with fry is smaller more frequent WC but I drip feed the treated water into the tank.. more like a very slow trickle than a drip but you get the point oh and I slightly overdose the prime.

 

Awesome. Thanks Rob and Pierre, really appreciate it.