Discus growth at different temp experiment

[pastry]

Hey, anyone know if it's worth the six bucks to read the discus growth to constant temperatures experiment that was published in aquacultural in a 2014 volume? Not that I think any crazy results were achieved but definitely curious since it was a legit (controlled) experiment. Just curious!

I couldn't find anything on SD on this when using search function.

[DJW]

Here is the link to the article:

http://onlinelibrary.wiley.com/doi/10.1111/are.12022/abstract

[MatthewJanssen]

What were the results? I don't think I can see them without paying.

[Skip]

it was talked about last year..

http://forum.simplydiscus.com/showthread.php?111570-Ideal-water-temperature-for-grow-out-(journal-article-results)

[strawberryblonde]

Pretty much the results stated that 28.4C (abut 83F) was the ideal temp for best growth and lowest mortality rates.

I've always grown mine out at a temp between 82F and 83F. Any higher and I see bacterial issues which I'm assuming is a result of faster growth of pathogens at higher temps. I've never gone lower than 82F so I can't speak to growth rates for that.

[discuspaul]

I've done the same as Toni for good growth - 82-83 - no more and no less.

[MatthewJanssen]

I was keeping mine in 30 degrees, guess i'll go down to 29 now.

[nc0gnet0]

If you have three tanks, one at 27.5, one at 28.4, and the last at 33 degrees.........

Assuming the exact same amount of food was fed each day,

What I want to know is what was water change schedule? (this is key)

I am not surprised that the results came out favoring the 28.4 temp, but as it stands, the test is far from conclusive.

We can probably surmise that 28.4 is better than 27.5, but what about 29.4 or 30.4? 33C is a bit extreme.

The idea behind increased temp is to increase the fish's metabolism, and thus it's appetite. So, with that said, if you were going to grow out fry/young juvies at higher temps (33C is too high IMO) increased feedings AND increased water changes would also be required. If those two are done, as well as the increase in grow out temp, then I would be surprised to see increased growth rate.

That being said, and human nature was it is, its pretty easy to dial up the temp and feed more, but, how many are willing to put the extra time into 2-3x a day water changes it would take to have success with the increased temps?

[DJW]

I noticed that they did the experiment in VERY soft water, 22 μS/cm and 0.08mmol/L (or 0.45 dGH).

[pastry]

If you have three tanks, one at 27.5, one at 28.4, and the last at 33 degrees.........

Assuming the exact same amount of food was fed each day,

What I want to know is what was water change schedule? (this is key)

I am not surprised that the results came out favoring the 28.4 temp, but as it stands, the test is far from conclusive.

We can probably surmise that 28.4 is better than 27.5, but what about 29.4 or 30.4? 33C is a bit extreme.

The idea behind increased temp is to increase the fish's metabolism, and thus it's appetite. So, with that said, if you were going to grow out fry/young juvies at higher temps (33C is too high IMO) increased feedings AND increased water changes would also be required. If those two are done, as well as the increase in grow out temp, then I would be surprised to see increased growth rate.

That being said, and human nature was it is, its pretty easy to dial up the temp and feed more, but, how many are willing to put the extra time into 2-3x a day water changes it would take to have success with the increased temps?

That's something I wanted to know about experiment... what did they do for wc's although temp was the variable.

Also, I kept mine at 86 but until about 9 months ago dropped it to 82 due to some tank mates. I still don't think it'd make a huge difference compared to WC routine but good to know.

[nc0gnet0]

Just to clarify, I grow out all my fry/young juvies at 28.3C. That said I do believe that increased growth can be obtained with temps of at or around 29.5-30.0C. However, doing this increases the fish's metabolism, and he will need to be fed more often. More food, plus elevated temps (ie. increased bacterial growth in water column) means more water changes. In the long run, for those of us with jobs that cannot do a wc while at work, it's not worth the risk.

Too much is made about trying to maintain the mythical 1" per month growth rate anyways. It's not a sprint, it's a marathon. Keep the water pristine, feed your fish but don't over feed, and they will reach their maximum potential. who cares if it takes another month or two.

-Rick

[Larry Bugg]

It's not a sprint, it's a marathon. Keep the water pristine, feed your fish but don't over feed, and they will reach their maximum potential. who cares if it takes another month or two.

-Rick

You give a lot of good answers and advice but this ranks up near the top. I have always hated the 1" per month for the first 4 months and you won't hear that come out of my mouth. Too many variables. I've never been able to reach those growth rates.

[Jack L]

Just to clarify, I grow out all my fry/young juvies at 28.3C. That said I do believe that increased growth can be obtained with temps of at or around 29.5-30.0C. However, doing this increases the fish's metabolism, and he will need to be fed more often. More food, plus elevated temps (ie. increased bacterial growth in water column) means more water changes. In the long run, for those of us with jobs that cannot do a wc while at work, it's not worth the risk.

Too much is made about trying to maintain the mythical 1" per month growth rate anyways. It's not a sprint, it's a marathon. Keep the water pristine, feed your fish but don't over feed, and they will reach their maximum potential. who cares if it takes another month or two.

-Rick

great point, i have seen in this round of grow out that different fish grow at different rates at different times in the same tank with same everything.
someone on this board early told me that happens with growing out, it is not a straight line progression, i'm seeing same thing.

[pastry]

You give a lot of good answers and advice but this ranks up near the top. I have always hated the 1" per month for the first 4 months and you won't hear that come out of my mouth. Too many variables. I've never been able to reach those growth rates.

Agree. Would also bet some of you guys would have a better experiment.

[strawberryblonde]

Yup, totally true that different discus grow at different rates. I think it's ok to give an "average" rate of growth, but just like human beings, some will be early bloomers and some will be late bloomers.

My favorite personal story is the discus I called Number Five. He was a pretty blue turq who lagged behind his 4 mates in the tank. I was SO DANGED SURE he was never going to be anything close to 6" that I stopped even looking at him after the first 6 months.

By 18 months of age he was a nice respectable 7" and by 2 years he was a full 8". He taught me to not count them out if they lag behind and seem to not be growing as quickly.

I currently have a yellow checkerboard who is lagging WAY behind the rest of his group. They all surpassed 6" by the end of 8 months and he's still poking along. In the last few weeks he's had a growth spurt and finally reached 5.5". He just wants to take his time and enjoy himself I guess.

[Antoniombdl]

One inch per month is an exaggerated growth rate..I'd say one centimeter, in other words less than half of it. Excluding the fast growers.

[Skip]

One inch per month is an exaggerated growth rate..I'd say one centimeter, in other words less than half of it. Excluding the fast growers.

discus.. and discus care are all different.. some get the results.. others don't..

[1077]

High quality fish from the get go,high quality /nutritional food's,good water quality would in my view be the driver's of growth/health.Do not believe one inch per month to be unreasonable but maybe not common for many outside those who breed them.
Do agree that higher temp's will increase metabolisim's and perhaps appetites along with possible bloating and poor water quality if one is not careful.(water changes)
Lot's of folk's way over feed their fishes and it has been this way forever with nearly all species of tropical's.
Is fine line sometimes between improved growth rates from increased feeding's and sick fishes.

[John_Nicholson]

One inch per month with young fish it perfectly reasonable if you know what you are doing and are willing to do the work.

-john