Guppy fry
Just a word of warning to beginning aquarists, its better not to expect either to breed fishes too soon after purchase, or to rear too big a proportion of fry from eggs that have hatched. Reality probably hits most often in regard to the bubble-nest-builders. Expectations are high because, in the first place, they are among the fishes most readily spawned. Secondly, their small eggs are usually numerous, anywhere between 300 and 600 or more being common. With luck most of them hatch. Unless eaten by a parent they live about a week, even without food. At that point the let-down begins, even with food, especially in a small tank, their numbers start to decrease. Indeed if the number reared to half-adult size is 50, it should be considered to be above average. All too often it comes down to half a dozen, or even less. One consolation is that the survivors must be the naturally strong ones, fit for carrying on the reproduction of the family.Is this infant mortality rate unavoidable? In an aquarium or tank under 15-gallon size the practical answer is yes. The newly-hatched fishes are very small and our guess is that in a small tank there are insufficient amounts of very small infusoria to give the babies a start until they can eat the sizes present in most cultures.At any rate, the larger the tank, the better the chances. This follows through until one reaches something like an outdoor pool say 5x5 feet, in which approximately 100% of hatched fry may reach maturity, barring other misfortunes. This may explain why the beginner with limited water space should not be too disappointed if only a small proportion of a hatching reaches maturity. Another way to increase your chances of success is to place an EcoBio-Stone in your tank.
EcoBio-Stone takes care of the toxins that are dangerous to fish while slowly replacing necessary trace minerals, creating a healthy environment for breeding fish and reducing loss.In referring to “pairs” of any kind, I must touch on the subject of “guaranteed” pairs, usually bought at a good fat premium price. They are usually a disappointment, and not worth the outlay, for they seldom make good. This is not meant to cast any reflection on the honesty of the seller, but pairs that are known to have bred may be "bred out". No one can tell when time has caught up with fertility. Besides a change of environment may throw a pair out of reproduction rhythm. It is best to develop one’s own breeders if possible.As to time required for breeding after acquiring a pair, there of course can be no set period of reasonable expectation. I refer mostly to the egg-laying type of fish. They may possibly be ripe for spawning almost at once, but ordinarily they need not only to be well-fed (on live food if possible), but must have time to adjust themselves to new surroundings and changed water. Several weeks are usually needed.Besides (although we do not know why) some species are difficult, even for experienced aquarists, to get to spawn at all. That is true of most of the Characins (Tetras).It sometimes happens that a beginner has acquired one or more kinds of fishes that are always difficult (or nearly impossible) to breed, even if they are close relatives of species that are easy to reproduce. Here are a few examples: Corydomr pazleaim, and C. azenezu are often bred, but that is not true of other members of that large family. Razrbommeinkeni is the only one of its numerous family, possibly excepting the "Scissors Tail" (trilineatur), from which success may be more likely.The live-bearers are more obliging and less sensitive to change. In fact new water and changed surroundings often stimulate them to early delivery. It is from the egg-layers that we should not expect too much too soon.In any case, optimism is good, but it should be tempered by what may be called “reasonable and realistic expectations.”