Female guppy still pregnant? (Over a month?)

Question

One of my fish, a female guppy, has been pregnant for a very long time and I'm worried about her. She was either already pregnant when I bought her or became so shortly after being introduced to a tank with male guppies. That was over a month ago, and she's still pregnant! Should I worry? Can she die from not dropping the fry? Is there any way to induce labor?

She's in a ten gallon tank in a temperature controlled room (no need for a heater, the room is always at 75 or so) with a few tankmates who don't bother her and some live aponogeton plants.

Answer 1

Ok, there's a few possibilites here.  Normal guppy gestation is 28-30 days.  However, cooler water temperatures slows down fish metabolism, so that may prolong a female's pregnancy.  Also, guppy females can hold their fry if they feel that conditions for birth aren't right.  This means that if they are in poor health, water conditions are poor, the tank is overcrowded or there isn't enough food available.  I have known guppies to hold fry while a tank was cycling and not give birth for up to 60 days.  They can also reabsorb unborn eggs or spontaneously abort a pregnancy if conditions are especially poor or if they are extremely stressed.  This usually happens early on in a pregnancy, but if she did that early on and then became pregnant again, it would have the effect of making her seem to be pregnant for a very long time.

Some things you can do that might help her to give birth are to check your water parameters and make sure your water conditions are good.  Do a water change with slightly cooler water.  Try to simulate a rainstorm with the water, sprinkling it over the tank when you add it.  Feed her with live or frozen bloodworms in the evening just before you turn out the tank lights for the night.  And hope for a storm.  The change in pressure will often trigger pregnant fish to drop their fry.  :p