Do Guppy Babies Need a Filter?

A water filter filters out waste and debris, keeping the tank clean and preventing cloudy water, overgrowth of bacteria and fungus and excess algae growth. Excess debris can alter the pH in your tank, which may cause health problems. It also makes your tank look dirty and polluted, and severely dirty water can interfere with you fishes' ability to find food, and cause a variety of fin and respiratory problems.

Guppy fry need clean water, and a filter is the easiest way to achieve this. They are especially sensitive to bacterial and fungal infections, so clean water is even more important for developing fry than it is for adults. However, guppy fry are so small that they are unlikely to produce the same amount of waste as adults, so they don't need as much filtration. For a 10-gallon tank, for example, a filter designed for a one- or five-gallon tank may work fine.

Frequent water changes can help you keep your guppy tank clean if you don't want to set up filtration. For small one- to 10-gallon tanks, plan on changing the water every two to three days. For larger tanks, change 10 percent of the water every few days, and change out the water fully every week or two. Frequent water changes have a downside, however. They prevent your tank from establishing an ecological balance and can cause rapid pH shifts. Thus you should use frequent water changes only as a temporary solution.

Guppies will reach full adult size in three to six months, and become subadults at about three months. When your guppy reaches subadult size—usually about one inch in length—you can move her to the adult tank. However, if you have lots of guppy babies, plan on investing in a larger tank. Guppies need ample room to swim and hunt for food. Generally speaking, you can have three to five guppies for every 10 gallons of tank water.