OK. I'm not trying to make you look or sound stupid but try this tick list.
1. Check to see if they are really guppies. Guppies are only live breeders and if they abort you would see little dead fish and not eggs. It’s like a human abortion women don’t abort eggs.
2. Calculate the tank size here is an on line calculator
Tank Calculator and use it to calculate the amount of salt. (See point 4)
3. If you are talking about a Salt bath this is what you should do.
A bath containing 1% table salt (NaCl) should be prepared instead. Infected fish are placed in the bath for 30 minutes to I hour at which point freshwater is added to the tank in order to reduce the salt concentration to 0.5%. The guppies are left in the second bath for another 4-5 hours. Afterwards, the treated fish are transferred to clean freshwater. This treatment should be repeated every 2-3 days until the fish recover.
4. Aquarium Salt (NaCl) does not change the pH or the hardness of the water.
Adding salt to your water lessens the amount of pathogens in the water, yet it is only slightly effective in treating fish ailments. I.e. it is not good as a preventative medication.
Salt is most effective when the concentration of salt changes. For example if you have an aquarium with little salt in it and you notice signs of stress or disease in your fish then the addition of a teaspoon of salt per 20L of aquarium water would in most cases be an effective treatment. Some marine aquarists do the opposite and give their fish a freshwater bath to treat similar ailments. In this case lowering the concentration of salt as apposed to increasing it (duh).
One theory is that pathogens, such as bacteria and protozoa, are mush simpler life forms that cannot compensate the change in salt concentration, but fish are able to compensate small changes in the concentration of salt. So changing the concentration of salt weakens the pathogens without harming the fish, giving the fish a better chance to recover."
Note:
A few fish do not tolerate aquarium salt such as Corydoras catfish and many live plants do not do well with salt in their water either.
4a but remember that you should change 20% of your water per week and not just the evaporated water. Also make sure the water that you are changing it with has been sat around the house for three days. You should also buy a water conditioner to add to this new water to kill the chlorine and use bio start. This will start the bio action in the water. This should be added to the water 3-4 days before adding it to the tank.
4b if you add just tap water your adults may survive but your fry will get deformed. I know I lost over 50 fry as I was doing this at the beginning thinking tap water was good enough.
5. Don’t use a breeder I have lost lots of fish this way.
5a. get a Fern plant that is really bushy and the fish that is giving birth will hang around it. Once the fish is giving birth moves it or if you are away at that time the little fish will hide in the fern. Also if you have 7 large stones piled up on top of each other the fry will hide in there as the adults can’t get to them.
6. The mother guppy releases a chemical which stops it from feeding for 48hrs once given birth so you fish will be ok until then
