How to stop stunt from early breeding?

[Natalie]

This is interesting and potentially important. Could you elaborate a bit more - any data on this?

Also wondering if a negative correlation between maximal size and breeding age has actually been established....I fear this too.

Thanks

I'll do some literature searches and see what I can find, and probably post info in a new thread. I don't want to derail the OP's topic too much.

Most fish research is done on food species, but because tilapia (for example) are cichlids, a lot of pertinent info can be crossed over into the pet world. I'll see what I can find. I know that bluegill, for instance, mature as quickly as 2 years in Florida because the water is warm year-round and they therefore grow more quickly. Further north, it may take as much as 6 years for them to grow enough to reach sexual maturity. Pretty neat.

 

[Water]

I work with fish, and the subject has been studied a lot in food fish (i.e., determining conditions for optimal growth). It's well known that the metabolic rate of fishes is dependent on water temperature, because they're poikilothermic (cold-blooded). Every fish has it's "optimal" temperature range, and the highest temperature at which it will grow optimally without causing adverse effects to the body systems. For example, tilapia (which are cichlids) have an optimal temp of 84-86 degrees.

There is a negative side to placing a fish in a constantly warm temperature to get the quickest growth: it shortens their lifespan. They reach maturity more quickly and therefore age more quickly and die more quickly. This isn't a problem for food fish because they're harvested and eaten once they reach market size. But it could take years off the lives of your pet fish. I used to want optimal growth in my pet cichlids and grew them out at a constant temperature in the low to mid 80s. I'm not going to ever do this again, because I didn't realize I was shortening their lifespans.

Not to sound rude or anything, but do you have any info/sources to back this claim up?


Would be nice to know whether or not I'm slowly killing my Flowerhorns with the high temps.. Although.. My hybrids hate the upper 70's. I'm a bit confused.

 

[peathenster]

I'll do some literature searches and see what I can find, and probably post info in a new thread. I don't want to derail the OP's topic too much.

Most fish research is done on food species, but because tilapia (for example) are cichlids, a lot of pertinent info can be crossed over into the pet world. I'll see what I can find. I know that bluegill, for instance, mature as quickly as 2 years in Florida because the water is warm year-round and they therefore grow more quickly. Further north, it may take as much as 6 years for them to grow enough to reach sexual maturity. Pretty neat.

Thanks. I suppose it might depend on the locality of the fish? e.g. some naturally live in waters with constant (high) temperature while others more seasonal?

btw, the FX5 is working great

 

[cacichlids]

That's a great setup, I'd leave them together unless he starts to cause physical damage or make her hide all the time.

Thanks

I took out the two pictus catfish and put them in the 180 gal Oscar tank because I keep thinking they might have eaten the eggs.

I'll see what happens now.

thanks again for all ur help

 

[Natalie]

Not to sound rude or anything, but do you have any info/sources to back this claim up?


Would be nice to know whether or not I'm slowly killing my Flowerhorns with the high temps.. Although.. My hybrids hate the upper 70's. I'm a bit confused.

Everything I'm saying is based on research that's been done on food and game fish. When things finally slow down at the end of the week, I'll do some searches and post the info here. This is the basis of what I'm saying...

In the wild, there is a seasonal fluctuation in temperature, so that growth of the fish also fluctuates. This is the basis for growth rings that you see in scales, otoliths, vertebrae, fin rays, and other hard parts. Each "ring" is based on a period of fast growth (hot weather) followed by a period of slow growth (winter)-- this together makes up one year. When we place fish in aquariums and provide constant high temperatures, they grow at a very high (some would say "unnatural") rate. Therefore, they reach a mature size and are capable of sexual reproduction earlier than their wild counterparts. It's also been researched that, because they mature more quickly, they begin the ageing process more quickly and have shorter lifespans than fish who were grown "naturally" (i.e., with seasonal fluctuations in temperature and fast/slow growing periods). I hope that all makes sense...

What i don't know is exactly how much is taken off the lives of the typical CA/SA cichlid. Maybe a year? I have a paper, exam, and lecture all due this week. After that craziness is over with, I'll look into finding the resources you're asking for.

 

[baldtaxguy]

Natalie, this is good stuff, thanks for what you've shared thus far. If you do start a new thread, please post a link to it on this one. I find this very interesting and makes me start to look at water temp much more differently, less now about the natural water temp species are native to, but now more toward their mortality. I've regulated water temp for brief periods to stimulate breeding and to reduce aggression, but I'm ashamed to be stumbliing upon this now as it relates to life span, but I'm glad you raised this. Thanks again-

 

[RD.]

While what Natalie has stated is to an extent true, numerous factors are believed to influence the longevity of fishes. Temperature is only one of those factors.

Temperature, diet, size, sex, reproduction, the genetic make up of each fish, as well as the overall environmental stress (from water quality, aggression, etc) all play a role in the lifespan of each fish.

Higher water temps typically equate to higher metabolic rates in a fish, take that same fish & feed it to meet or exceed its energy demands, and you will most likely reduce that fishes life span. By how much is impossible to say with any degree of certainty, and much of this will be dependant on numerous other factors besides just the water temperature.

IMO a high protein/fat diet will cause far more health issues including in many cases premature death in aquarium fish than water temperature. Many experts in this field consider fatty deposition of the liver (fatty liver disease) to be the leading cause of death in aquarium fish.

Some fun reading on this subject.

http://icb.oxfordjournals.org/content/44/6/494.full.pdf+html

That's just one opinion, here's a few more.
http://www.nature.com/nature/journal/v212/n5067/abs/2121277a0.html

http://www.sciencedaily.com/releases/2009/07/090727191906.htm

http://www.nothobranchius.info/pages/pubs/download/free/Valenzano_Temperature_2006.pdf


While there may be a fine line that exists between optimum temperatures and longevity, IMO the other factors combined FAR outweigh tank temperature. I personally see no problem with keeping a CA cichlid for its entire life at 80-81F, if all other factors are optimum, such as water quality, diet, and an overall low stress environment. For fish kept in captivity, a slightly elevated temperature could be viewed just as much a positive (immunity boost), as a negative. Having said that I wouldn't personally keep any cichlid in the mid 80's (or higher) for any extended period of time. I don't view those temps as adding any long term health benefits to a cichlid, and they may in fact have a negative effect over the long haul.

HTH

 

[peathenster]

Temperature, diet, size, sex, reproduction, the genetic make up of each fish, as well as the overall environmental stress (from water quality, aggression, etc) all play a role in the lifespan of each fish.

I recently heard a talk by Ad Konings and he mentioned that the normal life span of Boulengerochromis microlepis is only two years: growth in year one and reproduction in year 2. It's actually quite remarkable - they stop eating when they spawn, and would guard fry for as long as they can before they eventually starve to death. Interestingly, Ken has been keeping a single B. microlepis for at least 4 years. I suppose sex and what it leads to can be bad (physical and behavioral). But from the fish's perspective, what's the point of living a few years longer without being able to reproduce.

 

[RD.]

If you check the last link that I posted above you'll see that the turquoise killifish (Nothobranchius furzeri) only live a max of 3 months in captivity.
It's an interesting read regarding water temp & longevity in that species.

 

[peathenster]

If you check the last link that I posted above you'll see that the turquoise killifish (Nothobranchius furzeri) only live a max of 3 months in captivity.
It's an interesting read regarding water temp & longevity in that species.

I think a distinction should be made between "normal" and "abnormally prolonged" life span.

N. furzeri has one of the shortest life span (if not the shortest) among vertebrates. Most don't make it past 6 weeks in nature, and the maximum life span is about 12 weeks.

In the article you linked to, the "researchers" raised N. furzeri under lower temperature and found that they lived longer. Hardly surprising. Think about frogs that were buried underground for decades.

But the question at hand is not about how to make them live longer under abnormal conditions.....it's about whether constant temperature in the aquarium would shorten their normal life span. As mentioned above, I would think it depends on particular species - what they have adapted to in nature.