Questions about fry

Beth_obrien2424

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Okay, so I have been posting a lot on here recently because breeding is a topic I am not familiar with. It Is new to me and I want to learn and do what’s best for the fish.
Recently, my female molly had 8 fry. I also was accidentally given 2 guppy fry and a mystery fry in the bag when I bought some other fish.
I had all of these fry in a tank I had spare as this was very unexpected. However, I think the tank was too large and I couldn’t control the water quality for such tiny fish as they kept dying. So I moved them into a large breeder box back in my main tank (I only have 3 molly left but the 3 from the pet shop survived)

so my question, when are fry big enough for water quality not to be an issue? I had the small tank cycled, so I’m not sure what went wrong.
the issue being, my brother bought a tank that is currently cycling and is going to have 2 of the molly fry and the 2 guppy fry. So when are they big enough for them to go in his tank?
the others are going in my community tank when big enough not to get eaten, so there isn’t an issue there.
 
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Beth_obrien2424

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Bad water quality will be a problem for any fish of any age I'm afraid. If that's what you mean.
What are your current water parameters?
The water quality was fine until they went in there and I was told that this is because they are so small. I was told I had to do daily water changes, which I did, but they still seemed to keep dying. I checked the quality daily and it was a little over what it was supposed to be but not by much at all. I just figured that they don’t cope with any variation of water quality.
Someone told me that when they are big enough to move into the community tank, the water quality will be held by the other fish and I wouldn’t have a problem. However, some are going in my brothers tank on their own. So I’m not sure what to do about that
 

Salty&Onion

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I'd need more than "water quality is fine", I'd need numbers for ammonia, nitrite and nitrate in the water :)
I think you should keep the fry away from adults for 1-2 months more.
How big they are?
 
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Beth_obrien2424

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I'd need more than "water quality is fine", I'd need numbers for ammonia, nitrite and nitrate in the water :)
I think you should keep the fry away from adults for 1-2 months more.
How big they are?
It’s hard to give a number. They weren’t the colour next to the 0, like the main tank. But the colour wasn’t dark enough to be the next one down either. (Nitrate was 0 though)
They are about 2 weeks old now. Not big enough to not fit into the mouth of a molly
 

Salty&Onion

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It’s hard to give a number. They weren’t the colour next to the 0, like the main tank. But the colour wasn’t dark enough to be the next one down either. (Nitrate was 0 though)
They are about 2 weeks old now. Not big enough to not fit into the mouth of a molly
Your fry are too young to be put in with adult fish.
Your tank is not cycled.
 

Salty&Onion

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Read on cycling your tank here:

 
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Beth_obrien2424

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Your fry are too young to be put in with adult fish.
Your tank is not cycled.
My tank is 100% cycled. It went through all of the steps and eventually dropped back down to 0 on all levels. I’m not sure why after that it started to rise and I asked someone about it, and that’s when they told me that it was because I only had tiny fry in the tank and that fry require a daily water change for the quality to stay good
 

Salty&Onion

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So why your nitrates are 0ppm? Do you have any fast growing plants that could take up all the nitrtates?
Exact numbers, levels of ammonia and nitrites? Do a 75% water change to be on the safe spot.
Ammonia and nitrite levels started to rise?
There is a slight possibility that your cycle has crashed.
 
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Beth_obrien2424

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So why your nitrates are 0ppm? Do you have any fast growing plants that could take up all the nitrtates?
Exact numbers, levels of ammonia and nitrites? Do a 75% water change to be on the safe spot.
Ammonia and nitrite levels started to rise?
There is a slight possibility that your cycle has crashed.
Aren’t they all supposed to be at 0? They’re all pretty much zero but, like I said, the ammonia is slightly purple (supposed to be blue) but not purple enough to be at 0.25ppm.
the fry are in a large breeder box in the main tank now so I can keep them alive. There aren’t many left so there’s plenty of room in the breeder box. I don’t want to risk the tank again. I was just curious about how big they have to be before they can go on their own in a new tank (my brothers). In a cycled tank, should they be fine without constant daily water changes?
 

AdoraBelle Dearheart

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Someone told me that when they are big enough to move into the community tank, the water quality will be held by the other fish and I wouldn’t have a problem. However, some are going in my brothers tank on their own. So I’m not sure what to do about that
I think you've been getting some confusing information about water quality when it comes to fry and adult fish, and that's leading you down a confusing path.

Fish themselves don't regulate the water quality, exactly. How many fish and the type of fish does affect the bioload of the tank (which will affect ammonia/nitrite/nitrate levels), but we control the water quality ourselves with the use of filtration and nitrifying bacteria, plants that will uptake ammonia and nitrates, and water changes.

Frequent water changes are recommended for fry because they are often kept in relatively small tanks to grow out, and most people feed them more frequently than adult fish, from between 3-6 times a day. More food going in, means more leftover food and fish waste that needs to come out, so daily water changes is the best way to keep things fresh and the fry healthy.

A larger fry tank, lots of plants, and cautious but frequent feeding can allow for more stable water parameters than a little 5 gallon grow out tank. Your water quality might have been the problem, but it's likely because of the set up, rather than fry being weak. Eg, what size tank and what filtration did you use on it? Were there live plants?

Your brother's new tank still needs to be cycled, search the forum for how to do a fishless cycle, and to keep working on until ammonia and nitrites read 0, and nitrates less than 20ppm. Then it will be safe for fish, whether adults or fry. Adding some of the filter media or substrate from your established tank to his new filter or the tank will help to seed it with beneficial bacteria, and speed the process up.

What are you tank sizes and stocking, and what filters/live plants do you use? On your main tank, the fry grow out tank, and your brothers new tank?
 
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Beth_obrien2424

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I think you've been getting some confusing information about water quality when it comes to fry and adult fish, and that's leading you down a confusing path.

Fish themselves don't regulate the water quality, exactly. How many fish and the type of fish does affect the bioload of the tank (which will affect ammonia/nitrite/nitrate levels), but we control the water quality ourselves with the use of filtration and nitrifying bacteria, plants that will uptake ammonia and nitrates, and water changes.

Frequent water changes are recommended for fry because they are often kept in relatively small tanks to grow out, and most people feed them more frequently than adult fish, from between 3-6 times a day. More food going in, means more leftover food and fish waste that needs to come out, so daily water changes is the best way to keep things fresh and the fry healthy.

A larger fry tank, lots of plants, and cautious but frequent feeding can allow for more stable water parameters than a little 5 gallon grow out tank. Your water quality might have been the problem, but it's likely because of the set up, rather than fry being weak. Eg, what size tank and what filtration did you use on it? Were there live plants?

Your brother's new tank still needs to be cycled, search the forum for how to do a fishless cycle, and to keep working on until ammonia and nitrites read 0, and nitrates less than 20ppm. Then it will be safe for fish, whether adults or fry. Adding some of the filter media or substrate from your established tank to his new filter or the tank will help to seed it with beneficial bacteria, and speed the process up.

What are you tank sizes and stocking, and what filters/live plants do you use? On your main tank, the fry grow out tank, and your brothers new tank?
Yeah I think I’ve been given misinformation. Thank you. I was told that fry are too small to produce something (can’t remember what) and so they don’t cope on their own for a while.
my brothers tank is 45 litres and is currently mid way through a fish less cycle. I have cycled my main tank so I know how to do that part. I was just told some dodgy information about fry.
 

AdoraBelle Dearheart

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Yeah I think I’ve been given misinformation. Thank you. I was told that fry are too small to produce something (can’t remember what) and so they don’t cope on their own for a while.
my brothers tank is 45 litres and is currently mid way through a fish less cycle. I have cycled my main tank so I know how to do that part. I was just told some dodgy information about fry.
Yep, definitely dodgy info! There is a lot of misinformation out there, as well as well-meaning but wrong helpful people sometimes. They produce the same 'stuff' as adult fish, just in tinier amounts. But need more frequent feeding in usually smaller tanks, so need more water changes.


Did the tank you put them in have a brand new, previously unused filter on it? It's possible that the person meant that the fry were too small to produce enough waste to do a fish in-cycle I suppose. But doing a fish in cycle with fry is never a good idea anyway.
 
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Beth_obrien2424

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Yep, definitely dodgy info! There is a lot of misinformation out there, as well as well-meaning but wrong helpful people sometimes. They produce the same 'stuff' as adult fish, just in tinier amounts. But need more frequent feeding in usually smaller tanks, so need more water changes.


Did the tank you put them in have a brand new, previously unused filter on it? It's possible that the person meant that the fry were too small to produce enough waste to do a fish in-cycle I suppose. But doing a fish in cycle with fry is never a good idea anyway.
The tank I bought for my brother is second hand but I think they put a new sponge in there. Will that affect my cycle at all?
I have decided not to use a tank for the fry as they are growing as the breeding box is plenty large enough for them and then they will go straight into the tanks
 

Salty&Onion

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The tank I bought for my brother is second hand but I think they put a new sponge in there. Will that affect my cycle at all?
I have decided not to use a tank for the fry as they are growing as the breeding box is plenty large enough for them and then they will go straight into the tanks
If you remove a filter media that was cycled and had bacteria in it, yes, it will affect the cycle.
 
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