Hi, I,me going to get 10 platies and ten guppies at a ratio to 3 males for 7 females. I have a 50 gallon aquarium do you think that my tank will get crazy overun by babies

It will take a few months, but eventually yes. The young are old enough to produce themseleves around the 4 month mark for both species. Platies take about 1yr to become fully grown. Guppies take somewhere around 6 months. It will take a while before you starting having issues from overstocking. Having a fully planted tank would slow that issue and it will give the young places to hide.

Just curious, how will having a fully planted tank slow the overcrowding process?

Think about it, plant need nitrates and other waste products from the fish to grow

Overcrowding is overcrowding. I was referring to the issues normally seen from overstocking, ie. high nitrates, presence of ammonia. Plants will consume both, although big water changes may still be needed.

It seems to me that more plants would give more fry places to hide, thus allowing a faster population growth. When my tanks had fewer places to hide, the fry were eaten pretty fast by the bigger fish. As far as ammonia, nitrites, etc, wouldn't more plants mean the faster elimination of these compounds, thus allowing more fry to live? If more fry live then wouldn't population increase exponentially? Forgive me for the questions but my mind isn't grasping what your saying.

That's what I was thinking too, and that's true. I originally thought jrman83 was saying that plants would cause overstocking to actually be somewhat inhibited, but I had interpreted him wrong. What jrman83 is actually saying (I believe) is that, with plants, you can reach a more extreme level of overstockedness before you will actually start having water quality problems, because of the work the plants do to help maintain water quality. So in balance plants are both good and bad as far as fry-induced overstocking is concerned.

FWIW I start my planted tanks with platys (or guppies) and just let the population expand to whatever the tank (plants) can substain. As a result I have a more or less stable population that literally lasts for years and years.

Not sure about over crowding but I do have unmeasureable nitrate and phosphate levels plus a very high pH (8.4-8.8 api high range test kit) which would indicate a very low carbon dioxide level.


Actual population. ~30 guppies in a 10g tank that ran for 9 years from the original cycle trio. Sure various sizes but with 1/2 dozen or so reproducing adults.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Okay, question.....I thought you quit testing many years ago? (Nitrate) I don't get the unmeasurable amounts when I know what I have in my tanks and the hundreds of plants in some of them and still they will never get to unmeasurable amounts.

Only 30 Guppies after 9yrs and there was something wrong with the tank. Hopefully, you left out you pulled many out on a consistent basis to remain at 30? Otherise, it would be potentially hundreds. 6 females will produce well over 30 fry in just one month.

Actually I started testing just a few years ago for Fw and have always measured for marine systems. Plus I only measured extensively for testing peat moss in the substrate and just to understand why the planted worked. IMHO if you have measureable nitrates in a mature tank you don't have enough plants and/or are feeding too much.I do havest a 1/2 dozen when friends wanted some. But that was only every 1-2 years or so.

I think you're guilty of "linear" thinking. But then the key work in you statement was "potentially". Obviously not every fry grows to adulthood. So I wind up with 30 or so fish with some fry, quite a few juvies and 1/2 dozen or so reproducing adults. Tank stays that way for years and years. After a year or so it is impossible to tell who the cycle (parents) were.

Just my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

I don't know. Just seems your math is flawed. I have a 75g guppy tank that has doubled population in 3 months to now about 60, including any fry currently in the tank. This is with only about 6-7 producing females (more maturing everyday). I predict the population will double again in about 6 or so months, if not less. After every birthing, the number of females increases and the fry exponentionally grow. Keeping to that low of a population over that long of time would require specifically removing females and trying to keep it to only 6 or so that were producing.

All I was really saying was that there was much more to your story than what you said. 9yrs and only 30 Gupps does not happen naturally, unless your mortality rate was low or you removed them. If you had a low mortality rate then something was wrong with the tank, so I assumed you removed some.

Couldn't the adult (and perhaps juvenile) guppies just have kept the fry population in check by eating them? When I was a kid we had a tank with a somewhat similar situation but with platies and mollies. We never got rid of any fish or in fact really did any maintenance other than magnetic algae scrubbing and the VERY occasional vacuum and water change, and the tank flourished for years and years. (Not that I'm *recommending* this strategy, but...)

Well if you think about it as a female has more and more births the number of fry she produces increases substanstially. A good number for her first fry would be 10 but as she progress 30 can be an average amount. If half survive 170 fry is what my calculations are for one year

I think that in a tank with slightly harsher conditions only the strongest fry will make it. If the population explodes the weaker fry will 'naturally' die off. My parents have a very small pond in their garden with Gambusia in it and although there are always adults and babies there are never more than about 20 fish total. I think it's because the young either are eaten or the weak die off as soon as it starts getting overcrowded. Probably the same thing happens when you don't 'artificially' maintain water quality.

Limiting factor - Wikipedia, the free encyclopedia

^ what I think is happening.

Plus, I think Platys in the wild control their own population biologically/chemically depending on the nitrates in the water. Ex. they'll give birth to more males with high nitrates so that population doesn't increase as much.

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