Will breeding slow down growth?

[neutrino]

My short answer is ime not really, no. Give them good nutrition, good water, a suitable size tank without any undue stresses and (barring an incident of a health issue), they'll do just fine. Of course, individual growth will vary according to genetic and other factors.

My long answer:

Does the time and energy involved in holding, rearing, or protecting fry affect growth? Ehh... maybe to some degree, not something I've seen that much personally (and I've done a lot of fish breeding). But is it that simple?

If you were to do some science or professional aquaculture reading on the subject you'd find it's not as simple as some people understand it, not as simple as: energy is needed to produce eggs, therefore producing eggs reduces growth.

• Some appear to overlook the fact that at sexual maturity, whatever the age in an individual female, she's producing eggs no matter whether she's spawning or actually producing fry, the same as males are producing sperm no matter whether there are females with which to spawn.
• Studies on the subject have shown that-- all else being equal-- younger, smaller females generally produce fewer and sometimes lower quality (less nutrient dense) eggs than larger, more mature females. In other words, energy that is still being used for growth in younger females is unavailable for producing eggs. Older females are using less energy for growth, which becomes available for reproduction. So nature (biology) works to balance this out.
• Other factors affect growth and reproduction besides simply egg production or fry rearing, some of the big ones are diet, stress, and captive conditions of the fish (such as temperature, stocking levels, etc.). There's been a lot of aquaculture science done on this, especially including dietary and nutritional factors.
• Biochemical growth pathways have been found to be quite a bit more complex than biochemical reproductive pathways. Gets technical, more than what I've taken time to study, but the basic point is a lot of factors are involved in growth-- nutritionally, environmentally, and biochemically. With so much of it beyond the scope of the average fishkeeper, it's almost unavoidable that we oversimplify some things.
• Other not so natural factors are also involved, including chemicals in the water supply that can disrupt or alter the fish's normal biochemistry, growth, and reproduction. This logically varies somewhat by location, water source, etc.

So, what you see in your tank could be different from what I see in my tank for a lot of reasons, including differences in food, water, and tank setup. Makes a blanket statement one way or the other somewhat suspect imo.

 

[GreenTerror7]

I agree with what viejafish said. I've bwen keeping gts for 5ish years now and in my experience breeding does slow the growth rate down for males and females. Im not sure of the science behind it but just thinking logically, it seems that a lot of energy that could be used towards growth is used in trying to breed with the female or protecting the eggs. I've found with one individual fish that I raised from fry that the best way to increase the growth rate was introducing a male of similar size. Make sure that the male that you want to grow faster is slightly larger and more dominate. To put things in order, I found that keeping the fish with 2 similar sized males increased the growth rate the most but lessened his colors, keeping him alone was normal colors, normal (slow) growth rate, and keeping him with 3 females he had the nicest colors but did not grow a single centimeter over 4 months (I measured length, girth, height every month). Of course fish vary and everyone has different experiences but that was mine.

 

[convict360]

Some very interesting perspectives here, much appreciated guys

 

[lekkiandgas]

Constant breeding will slow down growth in both sex and specially the female because the resource to make eggs is greater than sperms. I have kept both single sex GT and breeding pair GT in separate tanks, the single sex GT always grow faster and bigger. I have also anecdotal evidence that if you allow a pair to breed constantly, it will shorten their life span as if once all reserved eggs and sperms are exhausted, the clock runs out.

I had my male gt from a baby but gave him a 8ft tank then he's in 6ft one now
I believe the big tank gave him room to grow
but yeah my f gt is so much smaller, same size as my clown loaches really

 

[lekkiandgas]

I agree with what viejafish said. I've bwen keeping gts for 5ish years now and in my experience breeding does slow the growth rate down for males and females. Im not sure of the science behind it but just thinking logically, it seems that a lot of energy that could be used towards growth is used in trying to breed with the female or protecting the eggs. I've found with one individual fish that I raised from fry that the best way to increase the growth rate was introducing a male of similar size. Make sure that the male that you want to grow faster is slightly larger and more dominate. To put things in order, I found that keeping the fish with 2 similar sized males increased the growth rate the most but lessened his colors, keeping him alone was normal colors, normal (slow) growth rate, and keeping him with 3 females he had the nicest colors but did not grow a single centimeter over 4 months (I measured length, girth, height every month). Of course fish vary and everyone has different experiences but that was mine.

I also breed gts and I personally feel, given the space in the tank that this didn't stop growth
he's 8,9in long and he breeds constantly and is 5yrs old, showing no signs of slowing down, I think the environment may be the reason, I am only speaking from my own personal experience of what MY gt does, but each is different