Fry Tank Maintenance
A good temperature for fry is 80°F, which gets their metabolism in high gear. However, this is not a necessity -- mid 70's is sufficient. At the higher temperatures, they will eat more and grow faster. This is important when you are born so tiny! After all, the bigger a fish you are, the better off you are in the fight to ward off parasites, disease, and, oh yes, bigger, hungry fish!
All this adds up to more work on the guppy keeper's schedule, for:
Fast metabolism + heavy feed schedule = frequent water changes!
First of all, this depends on the number of fish per gallon of water. Fewer fish mean less maintenance, basically. The best home for a batch of fry is a 5-gallon bare-bottom tank. It is not too large for them to find the food, and not so small that it allows for a stable, clean environment with a small inside box filter. Changing water at a rate of 50% a week keeps the water quality high, but make sure the replacement water is properly conditioned to remove chloramines and chlorine, and has the same pH and temperature as the tank water, so as not to shock the tiny inhabitants. Some guppy breeders do up to 100% water change will no ill effects.
Water changes themselves seem to spur growth. Nitrates building up in a tank seem to naturally slow the growth of most fish. This is likely a result of the natural order of things. Too many nitrates indicate that there is a population explosion, and slows growth in fish to make up for this. The only way to remove nitrates is through water changes.
Lighting is also an important aspect in the growth of guppies. Many breeders keep the lights on anywhere between 12-17 hours. Strong bright lights are not necessary, but guppies that live in a dim tank will often form. deformities of the spine. Lights should not be kept on around the clock so that the fish can rest and relax for at least 7 or 8 hours.
Remember that the first few months of a guppy's life are the most important. Fancy guppies are not solely nature's creation. People bred them to be as beautiful as they are and the only way to make your guppy become the best he can be is to give him the best food and best water.
See Tank Maintenance for more information on tanks and water changes.
refererence:http://guppyplace.tripod.com