Fry tank filtration

[Brhino]

I'm thinking about setting up a spare 10g I have as fry tank but one thing that puzzles me is filtration.

Now, I have a QT/Hospital tank, and like most people I keep media for that filter in a populated tank, so when I need to set it up, I move the media over and I have an instantly cycled tank.

a fry tank would be different, though, because the initial bioload would be so tiny. For example, I just had 8 corydoras eggs I managed to save that I tried to raise. 8 newborn corydoras fry in a 10g tank would generate an infinitesimal amount of ammonia. If I moved a filter into a tank with just 8 cory fry, the bacteria on that filter would quickly starve to death, and I would have an uncycled tank again, right?

What am I missing here? How do you provide effective biological filtration for a tiny bioload?

[Cliff]

For my past two fry tanks I just used the same approach as I do for the QT tank. I had a sponge filter running in my main tank that I just moved over

It seamed to work well for me. I lost very few fry in that tank.

Granted, there was more BB in the sponge than what was needed, but the BB die-off did not effect the water quality. I was also changing 50% of the water every second or third day.

[Brhino]

really? I've read you're only supposed to do small (but frequent) water changes in a fry tank because they're very sensitive to changing conditions.

[Cliff]

I had read that too. In the end, I had talked to a discus breeder here in the same city that I live in and I tried the process he uses for his discuss. It worked really well for 3 batches of acara fry that I raised before separating the parents into separate tanks.

I did take great care in making sure the temp of the replacement water was an exact match before starting the water change. If I remember correctly, these changes were typically closer to every second day

Smaller daily water changes would be better if you are concerned.

Edit:
I did test the parameters a few times before and after the water changes. There was no real big changes in the water parameters. Sometimes it would look like there might be a change in Nitrates, but it was always 5ppm or less

[Crispy]

+1 sponge filters always do the job for me.

[850R]

+ 2 to the sponge filter. Although with my molly fry I just let them take their chances lol.

[Abbeys_Mom]

I just used live plants and water changes on my last fry tank. Normally I use a corner sponge filter though.

[Sandz]

+3, I use a sponge filter that I keep hidden in the main tank. What I dont do is change the water, I just top off. I do my tests for water chemistry and if it ever gets out of whack I will change everything up but I rarely ever see a change with as you said, such a small bioload. When they get to the point where they will start affecting the levels I am ready to sell them to the LFS.

Something I didnt expect lately though was I just took in some fish. I was just experomenting with keeping them and in their qt tank (a 10gal with a AC20) they spawned a 40 fry batch. I just left the AC20 on there full flow and the fry are doing just fine.

How often/much do all you guys feed your fry? I currently am doing 4-5x/day.

[Brhino]

Wow... responses ranging from 50% water change every other day to no water changes at all. Makes it hard to decide what the best plan for me is.

I've also heard fry should be fed 4-5 times per day, but I don't know how you're supposed to do that if you have a job.

[Cliff]

I fed mine 3 times a day, seemed to work well. As both the wife and I work, that was the most we could do.

Also, you could just try the daily 10 to 15% water changes, see how it goes, and change things from there. Everyone's water is a little different, not to mention how everyone's set-up is different as well.

[Sandz]

Here Here to Cliff... everyone has a bit different set up. I feed 4-5x/ day but because I work I feed a little heavier in the morning, as soon as I get home (before I walk my dogs) and feed every 3 hours until bed time, so 7AM, 5pm, 8pm, 11pm... sometimes feed between those times if im feeling friendly.

So yeah... i got my dogs to keep me on schedule but other than that... its not easy.

[redbullbill]

I will throw another one at ya!!My fry tank is a 3gl cylinder with a ugf that came with it.It use to be my qt tank but i have my guppy fry in there.Its been cycled well over a year i just throw fish in from time to time to keep up the cycle.
With the fry in there i do 1 water change a week of 75%.They are fed 3 times a day.Keep in mind they have only been there two weeks.But they are growing like crazy. I feed them fry food twice a day and frozen baby brine shrimp once a day.

[dbosman]

The answer to your questions will vary due to others experiences and due to different fry.
Some fish and fry are more sensitive to water conditions than other. Some are more sensitive to being disturbed. Some spend most of their time at the bottom so vacuuming the bottom is difficult.
A well aged sponge filter for fry is good, as they will have micro-organisms to eat.
Many breeders of show quality fish still use box filters with marbles for weight and filter floss to catch the crud.