# temperature vs growth rate



## pomi (Oct 13, 2009)

I started with mbuna last year in May, in a 180 liters / 1 meter long tank. My first fish were 5 Caeruleus and 5 Elongatus Mpanga 3-4cm in size. By November they grew to around 7cm, also I added 5 Acei around 3cm in that period.

This year in January I added 3 Kingsizei around 3cm. Last moth I moved the fish to a 700 liters / 2 meters long tank and added a group of 10 Daktari around 3cm.

Now my Caeruleus are around 10cm, the Elongatus around 8cm, the Acei around 7cm and the Kingsizei around 5cm. Besides a male Acei who has grown very nicely to a size around 12cm(remember I got him at 3cm in November) I think the other fish I have grew quite slow. They look very healthy and have nice body proportions and I fed them various types of food.

So far I've kept the temperature in my tank at 24Ã‚Â°C, but a few minutes ago, I was reading some mbuna profiles here and I saw the recommended temperature is 78 - 82Ã‚Â°F (25,5 - 28Ã‚Â°C), so I changed it to 26Ã‚Â°C.

I know increasing the temperature accelerates growth rate, but what's the ratio of this? How much faster fish will grow with the 2Ã‚Â° temperature increase?

Thanks for patience in reading this and further replies.


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## greggb (Feb 4, 2010)

pomi said:


> I started with mbuna last year in May, in a 180 liters / 1 meter long tank. My first fish were 5 Caeruleus and 5 Elongatus Mpanga 3-4cm in size. By November they grew to around 7cm, also I added 5 Acei around 3cm in that period.
> 
> This year in January I added 3 Kingsizei around 3cm. Last moth I moved the fish to a 700 liters / 2 meters long tank and added a group of 10 Daktari around 3cm.
> 
> ...


I'm sure there are people more qualified to comment on this than me. But there are too many unknowns to be able to give you an exact formula for how fast your fish will grow. The amount/frequency you feed them, their overall comfort in your tank, the type of food you're feeding them for example.

My labs grew very quickly in a tank I kept around 76f. I doubt the slow growth is purely the result of temperature. What have you been feeding, how often have you been feeding them, and are your water parameters acceptable?


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## pomi (Oct 13, 2009)

I'm feeding them twice a day, the amount of food they can eat in 30-40 seconds. Every now and then I drop by mistake a little more, which takes them around 1 minute to eat.

From what I remember I fed them many types, mainly JBL brand:

Novo RIFT, Novo Malawi, Novo Granovert, Spirulina, GranaCichlid, Grana

Water parameters are OK, no problems here. The fishes seem to be doing great, very active, chase around and fight sometimes, breed often, color is ok, body, fins ok, etc.

My main wonder is how 1 fish grew from 3 to 12 cm in 6 months and others from 3 to 10 in 12 months.


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## FlyHigh (Nov 15, 2009)

water change frequency has a lot to do with growth rate as well. Among other things, removing the pheromones/hormones that the fish release into the water that slow down their growth rate is one benefit from frequent water changes. Maybe that was not constant among your two groups?


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## pomi (Oct 13, 2009)

I'm doing at least one 20-30% water change per week.


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## smellsfishy1 (May 29, 2008)

I find it to be true that growth rate will vary depending on temperature.
However, I also found that there is a point where raising the temp passed a certain point makes no difference.
In fact, too high can be detrimental.

Try to find the optimum range for your setup.
For fry I like the temp around 80*F.
Juvies around 78*F and adults around 76*F.

As stated above there are many other growth factors.
Water quality, tank size, population density, food........


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## Number6 (Mar 13, 2003)

FlyHigh said:


> removing the pheromones/hormones that the fish release into the water that slow down their growth rate


stress hormones are internal to the fish for sure, but external seems to be largely a myth. 
Water changes remove pollution and increase O2 which reduces stress, which reduces the GIH that the fish would be using to survive the polluted water. Fry love water changes!

and +1 for fry at 80, adults at 76


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## BigJagLover (Oct 25, 2006)

I think your ? about the acei growing faster is answered best like this. He's a male and the type of fish he is, is known for faster growth. When i worked at a LFS that dealth with Africans on a larger scale, we had people pick and choose out of or mixed african tank daily. They would always come back in a few short months, about 6, and say " this purple fish has out grown my other fish by 3 times. I did not beleve them so i took home some yellow labs and acei's and set them up in a 55 gallon. They where roughly 1" long at this time. As the months pegressed sure enough the acei got huge. My largest male was 4" in 5 months. I've never seen an african growth this fast. So I tried it out with a diffrent group a bout a year later. this time i went with red zebra's and acei'. Same size to start,1", and the same result. The acei's grew to 4" in 5 months again. The zebra's only got to be 3" at best.

So as you see here both times i had acei's with fenominal growth. So to me , the simply grow fast as a species.


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## greggb (Feb 4, 2010)

pomi said:


> I'm feeding them twice a day, the amount of food they can eat in 30-40 seconds. Every now and then I drop by mistake a little more, which takes them around 1 minute to eat.
> 
> From what I remember I fed them many types, mainly JBL brand:
> 
> ...


Another thought... breeding would be slowing down the growth of your females for sure, where they sit for... however long it is without eating, then turn right around and do it again. Was your male significantly larger than your females by any chance?


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## BillD (May 17, 2005)

Raising the temp without increasing food will not alter the growth rate. Fish don't burn energy to stay warm, so food foes to growth and maintenance.
As mentioned above water changes are at least as important as quality foods to growth rate. Also cranking the temp to increase growth rate may shorten the life of the fish. As well, higher temps mean lower oxygen levels and higher bacteria levels. Sometimes it is better to be patient.


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## pomi (Oct 13, 2009)

Thanks to all for answers. I had a feeling the small tank(180 liters) slows down growth rate a lot. That's why I made the upgrade to 700 liters a month ago. I will leave the temperature to 26Ã‚Â°C for now and see how things go.

And to answer greggb's question, yes, the males are about 1 inch larger then females, as expected.

To conclude my concern, the food and water change are OK, as I posted earlier?


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## DJRansome (Oct 29, 2005)

Not familiar with the Romanian foods, LOL. I'd up the water change percentage to at least 50% if you are interested in maximizing growth.


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## pomi (Oct 13, 2009)

DJRansome said:


> Not familiar with the Romanian foods, LOL.


JBL is not Romanian food )

JBL is a german company, big name in aquaristic. If you never heard of it, maybe it's a big name only in Europe.

Search the website on Google....

Concerning the 50% water change, I think it's too risky for me, cause I use water straight from the sink, cold water. I don't use it in combination with hot water to even it's temperature with the water from the tank, cause hot water, in my country, has large quantities of chlorineand other stuff not good for the fishes. If I change 50%, the temperature in the tank would drop too much.


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## smellsfishy1 (May 29, 2008)

If your hot water has chlorine and other stuff so does your cold water.


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## smellsfishy1 (May 29, 2008)

I forgot to mention one thing; use a good quality dechlor product and you should be straight.
It will detoxify what you need it to.


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## greggb (Feb 4, 2010)

pomi said:


> DJRansome said:
> 
> 
> > Not familiar with the Romanian foods, LOL.
> ...


IMO it's worth it to make your water changes worth it when you go to all that trouble. All you'd need to add to your setup is a large rubber bin that holds 15 gallons or so, and a pitcher. Pull the thermometer out of your tank and put it in the bin. Put your decholorinator (and salt, if you use salt) in the bin before adding the water, so it will mix well. Fill the bin with water, adjusting temp as necessary to get it within 2 or degrees or so (f, probably 1 degree c) of your tank temperature. Then drag it to right in front of your aquarium, if possible, and fill the tank with the pitcher.

If you're not doing sufficient water changes there's a good chance your nitrates have really accumulated. Depending on your bioload, your 20 to 30% per week changes may not equate to a reduction in nitrates, if nitrates are being added at a rate greater than 20 to 30% per week. If there's any chance of that being the case, you might consider upping your water change amounts. Or maybe that was the problem in your 3 meter tank, at any rate?


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## pomi (Oct 13, 2009)

I posted earlier that my water parameters are OK. Here are the result of the tests made today.

NO2 is 0, maybe 0,1
NO3 is close to 0
pH is 8
GH is 12-14
kH is 10-14
temp is 26C


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## DJRansome (Oct 29, 2005)

I think the reason the water changes keep coming up is that seems to be the #1 most successful way of speeding growth. It's not a water parameter thing. I'm not sure anyone knows for sure why it works, but it does. Perhaps some toxin in the water that we don't measure is being removed. I understand what you are saying, that it is not an option for you to put 50% cold water into the tank. And perhaps the holding tank to achieve room temperature first is not worth the bother to you. Good suggestions given your request though!


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## pomi (Oct 13, 2009)

So, I taken you advice and did a 40% WC about a month ago and watched the fish. They seemed well so I got boldier and took another 40% after 3 days. The fish were still fine so, since then, I'm doing 2 WC a week, 40% of the water changed every time.

Now I'm waiting to see if they grow faster than before. Will keep you updated.


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