# how many shrimp You really need to start colony?



## brook39 (Aug 12, 2016)

When I started my RCS colony i've had only 3 females, now I have around 100, I've just got 3 tigers, and I'm wondering do I really need to get at least 10 to start new colony? If You get shrimp from the store where they're in large numbers in the tank, females might be pregnant already,right?


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## BettaBettas (Aug 21, 2016)

right. I started out with 3 shrimp. 1 male 2 females.


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## sohankpatel (Jul 10, 2015)

It depends on if you are choosing your shrimp or getting them shipped to you. If you can sex the shrimp right there, then you can get by with 3 or 4, 2 or 3 females and one male.
10 is when you are shipping them, because it basically guarantees that you will get at least one male or female.


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## Matuva (Jun 8, 2015)

Basically, 1 male + 1 female will be able to build a colony.

As for shipped shrimps, yes, 10 is an average good choice. Though, I had received a batch of 12 blue Topaz. 1 died few days after arrival, and I had 11 juveniles growing. Once mature, I realised I had 1 female and 10 males.
The female get berried, but unfortunately, none of her shrimplets survived, and she died before getting berried again. I now have 10 very nice Topaz male


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## Turningdizzy (Apr 5, 2014)

1+1/boy girl, is all it takes. It seems shrimps come with the "Love Bug" hardwired into their very existence. I guess that is to be expected when you live near the bottom of your local food chain. Regardless of the number of shrimp that you buy online, you are never guaranteed mixed sexes unless you buy from someone that can sex them confidently for you. Basically, the more shrimp that you buy, the better the odds you have for mixed sexes. As mentioned, 10 is a good number, 20 is a better number, etc, etc.


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## Freemananana (Jan 2, 2015)

The odds of you not having at least 1 male and 1 female in a group of 10 is like 1% if I'm remembering the math right. The odds for the three pack is about 88% though. I think? 

1-(1/2)^n

"1" is 100% or the absolute. The 1/2 is your chance of it being a male (or female, doesn't really matter). "N" is the number of shrimp you buy. I think. Maybe "N" should be the shrimp minus 1 so that you can assume you have either a male or a female and you only need the other. If that is it, then you have a 75% chance of having a pair with just three and 50% chance with two, which sounds more right.

1=0
2=50%
3=75%
4=87.5%
5=93.75%
10=99.9%
20=99.9999%

Yada yada, something like that. I'm thinking 5 is pretty much a sure fire thing, 3 is pretty good odds, and 10+ has got to be a go.


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## BettaBettas (Aug 21, 2016)

@Freemanana to much math for me
*closes door behind me*
lol


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## natemcnutty (May 26, 2016)

Keep in mind that you'll probably have better luck with juveniles, and that would be before they become saddled / berried.

I would start with 5-6 minimum for a several reasons. First, you have better odds of getting one of each. Second, your colony will grow faster if you end up with more than one female. Third, sometimes things go wrong even though everything looks good, and having "spares" can be helpful. Finally, you can be selective with breeding if you want - hard to tell qualities at the LFS sometimes 

Sent from my Nexus 6 using Tapatalk


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