I just brought home a tank full of guppies, some are pregnat

[KittenFishMom]

I just brought home a tank full of guppies I bought off Craigslist. The seller didn't seem to know much about the guppies, but she said some where pregnant.  I wasn't expecting pregnant females. Do I need to do anything special with them? Do they need to be seperated and/or removed from the tank? The seller said she had also dumped in a bowl of baby guppies a friend gave her. 

The seller had pulled all her plastic plants out, completely clouding the water, before I got there. There were no live plants. I brought all the water home to let it settle here, to try to see what I have. I added a bunch of hornwort and snails and scuds to start cleaning the tank. I replace the seller's filter with a sponge filter because her filter had no prefilter.

Any advice is welcome. From the photo of the tank in the craigslist post I was expecting a few fish and a 10 gallon tank.  There are a lot of fish.

[lefty o]

there's a few ways to go. if you want tons of babies ( which you will likely get no matter what), you can separate the pregnant females out to give birth. this will reduce predation of the babies. you can also just leave them all in a tank together, and this will reduce the number of babies that reach maturity via predation. in reality, either way, you will have a herd of guppies in no time. almost always a given if you have both male, and female guppy's.

[KittenFishMom]

@lefty o Thank for the info. I guess I should work on trying to serperate the males from the females over time. I don't really want a ton of babies.  I think I have more than enogh fish now to keep me very busy for awhile.

[Patrick_G]

I would probably leave the old filter for a while, if you’ve got a tank full of guppies you’re going to want the beneficial bacteria in the old filter while your new one gets cycled. 

[Levi_Aquatics]

I would suggest leaving the females in the aquarium and just letting them give birth there. This will be the easiest for you and the adult fish kind of "self regulate" how many fish are in the aquarium by eating some of the fry.

[Crabby]

On 1/5/2022 at 3:48 PM, Levi_Aquatics said:

I would suggest leaving the females in the aquarium and just letting them give birth there. This will be the easiest for you and the adult fish kind of "self regulate" how many fish are in the aquarium by eating some of the fry.

I agree with this - depending on the amount of fry you want, just add or remove some hornwort. The more hornwort, the more fry that will survive. But the adults will essentially not allow the population to grow uncontrollably.

[Beardedbillygoat1975]

A 10 g tank and a horde of guppies can be difficult to manage in terms of the tank parameters. I’d keep a careful eye on your ammonia, nitrite and nitrate. I’d do water changes 25% every other day for a week just to keep things copacetic and then stretch it out to every 3 days the following week, 2 days then 50% weekly. 
These are masters of reproduction and they will stretch the limits of the tank and perhaps your abilities as an aquarist. I would get some crushed coral to buffer the water and keep the kh, gh and ph up which is what they like. 
Under not over feed they are always hungry. I’d keep the temp in the low 70s to slow down reproduction and to reduce aggression. 

[KittenFishMom]

My maternal instinct kicked in, and I felt like I should save all the fry that I could.

Now that the water has clear and I see how many fish are in the tank, I think it will be best to rehome some and let the adults try to keep the population in check. I was thinking that move the males to a different tank would slow things down, but I just read that female guppies can store sperm for up to 8 month, so it looks like I will be having a lot of guppies for a while. Some males look pretty fancy, but I know mixing varieties will decrease the fancy fins. 

They are very pretty to watch swim around the tank.

I will start slowly transitioning them to well water and see how the population holds up.

[lefty o]

On 1/5/2022 at 10:18 AM, KittenFishMom said:

My maternal instinct kicked in, and I felt like I should save all the fry that I could.

Now that the water has clear and I see how many fish are in the tank, I think it will be best to rehome some and let the adults try to keep the population in check. I was thinking that move the males to a different tank would slow things down, but I just read that female guppies can store sperm for up to 8 month, so it looks like I will be having a lot of guppies for a while. Some males look pretty fancy, but I know mixing varieties will decrease the fancy fins. 

They are very pretty to watch swim around the tank.

I will start slowly transitioning them to well water and see how the population holds up.

females will generally have up to 4 sets of fry per breeding (number can vary). guppies are fun to watch, no doubt about it. once you get the population balanced, youll be happy with them.

[JMiller2020]

Honestly imo just leave them all together so the adults can help reduce the population.  Unless your planning on giving away tons per month or you have a pure strand and want to keep the males etc.. to trade with a LFS or whatever.  Kids are always mad that we can't save all 100 babies a month lol