Mosquito fish/Gambusia not reproducing?

[kj5kb]

Last summer 2008 I bought 12 Gambusia to keep down any critters in our outdoor fountain. Always wanted to 'try' some since I was a kid...and actually found some locally.

So...in mid Oct, 10 were left; I brought them inside to a 20Long shared with ~ 10 platys and recently some amano shrimp.

...been almost 8 weeks now, and no fry...I thought these were considered an invasive species...???? 1 female looks quite chubby, but nada so far. I can only positively identify ONE male...maybe he's shooting blanks? Tank is full of plants, plenty of hiding areas...

???

--Don

 

[SchizotypalVamp]

They are most definitely an invasive species, and it is common to be stuck with more than you can handle..maybe the platies have been eating the fry?

 

[derekp]

Yes I agree on the platies. I had platies for a year and only got one baby out of them. They definitely have no problem eating their fry. As for the gambusias. I stuck about a 100 in my pond this summer from a nearby creek. I now have close to a 1000. But I don't have a mosquito problem . Try seperating the platies and the gambusias if you have another tank.

 

[boostnbuds]

They breed readily. I would say your fry are being consumed. There are things you can do to give your babies a better chance at not being eaten. Good ground cover...the babys instinctivley sink after birth, if theres no where to hide their sitting ducks. Breeder traps work on the same idea. Isolate the pregnant female a day or so before birth (not to early, the stress could cause a "miscarriage") and the babys will safely fall into a chamber protecting them from the mother (who will eat them).

 

[kj5kb]

Fair 'nuff...I'll move a few of the plumper females into the nursery tanks with fry only + better hiding places and see what happens.

 

[Notophthalmus]

Sometimes ramping up the temp by 5 or 10 degrees will induce the female to give birth.

 

[chenya]

Another option is to fill the tank with lots and lots of plants. Java Moss works well. I too agree that the platies may be having themselves a little snack. With plenty of hiding places you should have some survive though.

 

[jpappy789]

Also consider that the preggo females will eat them...they need to be removed otherwise they will too snack on their fry.

 

[kj5kb]

I neglected to mention the 20Long they're in is packed with plants...but it's sand substrate with no rocks. One 10G nursery tank has a layer of ~1.5" river rock, the other has large gravel; both do a good job of hiding newborns. Might try cranking the temp up to 82 and see what happens, too