The easiest way to get free freshwater fish is to buy one pregnant fish or a few starter fish and keep them in a healthy, baby-safe tank.
Things You'll Need
- Fish tank
- Pregnant molly, guppy or platy
- Adult male and female mollies, guppies or platys
- Floating fish food
- Real or artificial plants and ornaments
- Old nylon stocking
- Rubber bands
- Small secondary tank
How to Get Free Aquarium Fish
Choose a pet store where the fish tanks look bright and clean, and where the fish are active and look healthy. Search for pregnant female fish; in guppies, platys and mollies, which are live-bearing fish, you can see the bulge in the female's abdomen and a dark "gravid" spot on her vent, near the bottom fins.
Ask a patient store employee to net the specific fish you select. Don't make this request during the peak store hours, when there are many customers. If you're unable to find a pregnant fish, ask the employee to help you choose one male and two female fish of one of the species named.
Add fish carefully to a healthy freshwater tank. Be sure the tank has a layer of gravel on the base and a number of real or artificial plants and ornaments, which provide hiding places for the young. Use an automatic aquarium heater to keep the tank water at 78 degrees or above; most modern heaters are pre-set at a temperature range for tropical fish.
Use a small circle of nylon stocking material to cover the intake of the filter; secure it with a rubberband. This will prevent the babies from being sucked into the filter.
Feed your fish pellets or flakes that float. This will encourage the adults fish to eat from the top of the tank, and will allow uneaten food bits to settle to the bottom, where they are available to the young fish. If you use flakes that sink, the adults and young will be competing for food at the bottom.
Periodically shine a flashlight under ornaments at the bottom of the tank (from outside the tank), checking for the fry. Most adult mollies, platys and guppies will leave their young alone, but other fish might chase them or eat them. If you have other species in the tank, provide extra hiding spots--artificial aquarium grass is helpful--or transfer the young to a smaller tank that is also well-planted with hiding places, so they'll feel secure.