# Fry Growth and Water Changes/Plants



## Endler Guy (Aug 19, 2007)

Have any of you noticed a difference in growth rates between fry raised in planted tanks with minimal water changes vs. non-planted tanks with large, frequent water changes? 

I just reunited 2 molly fry, not quite two months old, that were in my endler tank with the rest of their family. They had been kept in my 55 gallon planted tank with my endlers. I kept the two in there to help with algae. Mollies have mouths adapted to scraping surfaces. One of the "females" turned out to be male and I wanted a true Endler species tank. So, I moved them. They did look pretty big in the endler tank but I thought that was because the endlers were smaller. When I put them in the 10 gallon with an undergravel filter, I could clearly see that their siblings were about 1/2 - 3/4 the size! These two were barely shy of the adults lengths and a little more robust. They're higher from top to bottom and thicker from side to side.

The ten gallon gets a 50% water change weekly. There shouldn't be anything building up. The 55 has had only top-offs for the past couple of months but has ever-growing flora. 

In Diana's book, a breeder states that his fry have less deformity in his planted fry tanks but I assumed it was from lack of ammonia. It could be a lot more than that. 

So, could it come down to the size of the tanks or that plants were involved?


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## mistergreen (Mar 3, 2007)

there are probably a lot of factors.. hard to say.


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## Endler Guy (Aug 19, 2007)

mistergreen said:


> there are probably a lot of factors.. hard to say.


It'd be easy if they had both been the same sized tanks with one being planted and one not or if one had water-changes and the other not but, like you said, it's hard to say. I believe the plants had everything to do with it. How could they not?


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## dwalstad (Apr 14, 2006)

Endler Guy said:


> In Diana's book, a breeder states that his fry have less deformity in his planted fry tanks but I assumed it was from lack of ammonia. It could be a lot more than that.
> 
> So, could it come down to the size of the tanks or that plants were involved?


Thank you for reporting your observation. Informal though it may be, it supports what I've witnessed in my own tanks.

Planted tanks are healthier for fish.

Plants take up ammonia, nitrite, and CO2 plus give off oxygen. The system is richer biologically (more nutrients, bacteria and protozoa) without the toxicity.

Soil particles and plants provide more (logarithmically more) surface area than a tank with just water and gravel.... More "little homes" for bacteria and protozoa. Most of these critters live attached to something (as opposed to living in the water). Fry can continuously feed on the protozoa associated with the plants and soil. Its not surprising that they grow faster.

Diana
P.S. Enjoyed your poem!


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## Carissa1 (Aug 25, 2007)

I wonder if growth rate of fry is affected by the size of the tank they are in. I have a couple of molly fry in my 10g that are taking what seems like forever to grow. The guppies in the same tank that were actually born the same day have been full grown for a month or more and are about 3x the size of the mollies. I know guppy's life spans are much shorter which accounts for some of the difference in growth rate. If I moved the mollies out to my 32g tank maybe they would grow faster? Both tanks are planted.


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## dwalstad (Apr 14, 2006)

Carissa1 said:


> I wonder if growth rate of fry is affected by the size of the tank they are in. I have a couple of molly fry in my 10g that are taking what seems like forever to grow. The guppies in the same tank that were actually born the same day have been full grown for a month or more and are about 3x the size of the mollies. I know guppy's life spans are much shorter which accounts for some of the difference in growth rate. If I moved the mollies out to my 32g tank maybe they would grow faster? Both tanks are planted.


Hard to say-- without a valid control. That is, Mollies from the same batch put into the 32 g and the 10 gal at the same time.


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## aquabillpers (Apr 13, 2006)

Fish do better in planted tanks. I don't think that there is much disagreement about that.

However, commercial breeders use bare tanks and pools and frequent or constant water changes simply because they want to get a large number of fry to market size as soon as possible, and that environment is best for that. I don't believe that there would be much disagreement about that either.

So if one wants to raise 200 bettas from a spawn to sell, he or she will opt for a bare aquarium, shallow water, daily water changes, and specialized food for the first few weeks. If, on the other hand, one wants to raise a smaller number of fry, a NPT is a great place to do it, and they will do quite well on the tiny organisms that live there. It would also be fun to watch them feed and grow.

Bill


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## Endler Guy (Aug 19, 2007)

dwalstad said:


> Thank you for reporting your observation. Informal though it may be, it supports what I've witnessed in my own tanks.
> 
> Planted tanks are healthier for fish.
> 
> ...


Thanks for you input and further explanation, Diana. If only I had more space to do a scientifically controlled experiment.

Glad you liked the poem.


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## Endler Guy (Aug 19, 2007)

Carissa1 said:


> I wonder if growth rate of fry is affected by the size of the tank they are in. I have a couple of molly fry in my 10g that are taking what seems like forever to grow. The guppies in the same tank that were actually born the same day have been full grown for a month or more and are about 3x the size of the mollies. I know guppy's life spans are much shorter which accounts for some of the difference in growth rate. If I moved the mollies out to my 32g tank maybe they would grow faster? Both tanks are planted.


My Endlers and guppies seem to mature faster than my mollies. The Endler and guppy broods are starting to run into each other now so it's hard to tell which babies are how old, especially the guppies since there are so many of them.

After a month, your guppies are 3x the size of your mollies of the same age? At that rate, you're mollies won't mature for at least another four months or so. I don't know what's at work there. At first I thought maybe allelopathy for fish but since I had mine in a tank with Endlers, that must not be it. A possibility is that your guppies are out-competing your mollies. Mollies are more vegetarian than guppies so, if you've taken measures to eliminate algae in that tank, it may be a factor.

Ever since I've increased my feeding to over a gram a day in my 55 (to match Diana's feeding of her 50), I've noticed that my Endlers don't seem to care about the food itself but I am forever seeing them eating off plants and the substrate. They used to LOVE this food too, and I wasn't underfeeding. I may have been underfeeding the plants, but not the fish.


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## Endler Guy (Aug 19, 2007)

aquabillpers said:


> Fish do better in planted tanks. I don't think that there is much disagreement about that.
> 
> However, commercial breeders use bare tanks and pools and frequent or constant water changes simply because they want to get a large number of fry to market size as soon as possible, and that environment is best for that. I don't believe that there would be much disagreement about that either.
> 
> ...


I agree with everything you've said. Are you a commercial breeder?


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## dwalstad (Apr 14, 2006)

aquabillpers said:


> Fish do better in planted tanks. I don't think that there is much disagreement about that.
> 
> However, commercial breeders use bare tanks and pools and frequent or constant water changes simply because they want to get a large number of fry to market size as soon as possible, and that environment is best for that. I don't believe that there would be much disagreement about that either.
> 
> ...


I think Bill has explained the situation beautifully.

I've raised many, many babies in NPTs without water changes. When I raising Tangyikans to sell, I had at least a 100 juveniles in a 20 gal long with no water changes for months. Right now, I've got 20 juvenile Yellow Rainbowfish ("Herbies") in my 55 gal. I've not changed water for last 4 months since they were born. Plants grow like crazy, and fish are doing just fine.

Yes, folks there are fish hormones, but many stimulate growth-- not inhibit it. Also, bacteria will degrade hormones. So many variables....

Water changes are absolutely essential in tanks without plants. Thus, commercial fishbreeders understandably swear by them.

However, NPTs are a whole different ballgame. In my opinion, they're just fine for raising baby fish-- more fun and a lot less work.


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## helenf (Mar 24, 2008)

I've been reflecting on the amount of life in my NPT compared to my other planted tanks.

The fish look fine, the plants are doing great, the apple snail doubled in size in 2 weeks. Pond snails have appeared in large numbers. I had a dragonfly larvae give me a fright before I removed it (thought it was a spider - yeah, pathetic for an Aussie), and I'm seeing these weird little bug things that stick onto the glass like small translucent mounds. There are small amount of all sorts of algae - not just brown and green, but some hair algae too, which I never saw before. Less algae than my other tanks so far, mind you, but more variety of it. 

And this is just the stuff I'm seeing. 

Seems to me that my NPT, for all it is smaller and probably has less stable water parameters than my other tanks, due to the size difference (certainly the temperature and PH vary more), is more conducive to healthy life of all sorts. And I reckon that must be good for the fish than something more sterile and with less variety.

Pity about those snails though, and the hair algae. I wouldn't mind the tank being less conducive to those particular forms of life...


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## Kubalik (May 24, 2008)

I am not very expirianced but is the PH same in both tanks ? i think mollies like higher PH ...


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