Raising fancy guppy fry to achieve a maximum growth rate and superior specimens requires an attention to detail that separates the casual guppy breeder from the exacting and dedicated professional. If raising fancy guppies was as easy as people would like to lead you to believe, we'd all be raising championship-quality show guppies.
As I have mentioned repeatedly on this site, as it applies to techniques and regimens on any aspect of fishkeeping, I will not tell you that there is only one way to do things and that way is the way I choose to do them. It is my goal to simply tell you how I have done it for 60+ years and hope that you will follow my lead to see if my techniques might afford you the same level of success that I have experienced over that time.
Let's start with what to do in order to assure that you save the maximum number of fry from any drop. This begins with the birthing tank. For almost everything I do on my fish room, the 10 USG tank is my weapon of choice. There are very few things that this particular sized tank can't be used for.
I have all of my female fancy guppies drop their broods in a bare-bottomed 10 USG tank. I will employ either two corner filters or two sponge filters, running at high output, when I first place the female in the tank, and begin lowering the output over time as she gets closer to the drop date. This helps her achieve a level of calmness that is conducive to the production of large quantities of healthy fry.
I use a few different items to provide hiding places for the fry, but I must tell you that my preference varies from strain to strain, and oftentimes from one specific female to the other. Additionally, on rare occasions, I will employ breeding traps, but again, based on certain strains and fish and using them can be a trade-off between saving the maximum number of fry from a rare strain, with the threat of losing the female to stress. I'll explain this in greater detail, later in the article.
The first scenario that I would employ would be the 10 USG tank, with a live plant - and lots of it. My first choice is always java moss as it provides the maximum protection for fry to hide in. I will generally stuff the tank full of it, but leave a small section where it is about 1 inch from the surface so the female has at least one area where she can swim, unhindered. As the female gets closer to dropping her fry, keep the filter turned down and the lighting to a minimum. It's easy to tell when the female is preparing to begin dropping as she will become virtually motionless, usually at the surface or just below it. Sometimes, though, she will find a nice secluded spot deep within the moss. She will give the appearance of hovering with her pectoral fins fanning rapidly. If left undisturbed, there is a very strong likelihood that she will drop all of her fry without incident and very few fry, if any, will be lost due to predation. The more you disturb the female during this time, the more fry you can be assured will get eaten.
There are a few different situations that can arise as the female is going through the process of birthing. If the fry are fully developed, they will generally dart to the bottom of the tank. This is why it is so important to be sure that whatever you provide in the way of cover is extremely dense and fills the entire tank, top to bottom and side to side. Some breeders prefer to have a thin layer of natural colored gravel in order to provide the fry with something to blend into, but I prefer a bare-bottomed tank. I would suggest you try both methods to determine which you are more comfortable with, but there is one more thing to consider in this regard. Oftentimes your fry will be born slightly premature and will not be fully developed. Generally they will not be able to swim and will just scurry across the bottom of the tank. Even netting them in this delicate condition can result in large numbers of dead fry. I prefer to siphon them off the bottom of the tank into a container. At that point I can decide to move them to another tank or wait for the female to finish and place them back into the birthing tank. So as you can imagine, having a clean bare-bottomed tank makes it much easier to siphon up the fry while they are in the perilous state and virtually assured of becoming lunch, once the female starts move about after dropping all of her fry.
After a few minutes of laying on the bottom, the fry will generally begin to migrate to the surface at which point they are in greater danger of being eaten. The more densely packed your fry cover, the better chance of survival they will have. If you are fortunate enough to catch your female in the act of dropping her fry you will have an opportunity to save as many fry as possible by employing one of two methods. The first is to watch her until it appears that she has dropped all of her fry at which point you can net her and move her to a recovery tank. It's best to allow her some time to recuperate before being once again exposing her to the incessant pestering of males looking to mate with her. A little rest for the weary will assure that your prized female will fully recover from her ordeal and will reward you with many more fry in the future.
The other method entails attempting to net each fry as they are dropped and moving them to another tank. If you are going to use this technique, be sure that the water parameters in both tanks are identical, lest you shock the fry. Personally, I prefer the fist option as there is much less chance of disturbing the female and sending her into a fry-consuming tizzy.
Of course there is also the option of using a breeder box which will prevent the female from eating any of her fry. It is extremely important to carefully observe any female that you subject to this confinement. It is very common for females to die from stress when using breeding traps so weigh this choice carefully.
Feeding Guppy Fry
Here, again, I want to reiterate that this topic is another that is fraught with argumentative conjecture and opinion. All I can suggest is that you do your research, evaluate everything that you have discovered and make up your own mind as to what are the most prudent methods to raising healthy fancy guppy fry to adulthood. I'll discuss your options, one at a time.
This product is dispensed from a tube and I must admit that I haven't seen it in such a long time that I cannot tell you what the ingredients are. Google will have to serve as your friend on this one. What I can tell you is it is not a product that I would ever consider feeding to any of my fish. It is extremely easy to foul your water and there are just so many other alternatives that I would be hard put to understand why anyone would resort to feeding this to their fish. I'm not aware of any serious fancy guppy breeders that feed this to their fry.
Powdered Flake Food
This is a perfectly acceptable first food for your fry as it is convenient and easy to use. Great care must be take not to overfeed your fish because this food is no different in it's ability to foul your tank if overused. A tiny pinch goes a long way. It is recommended that you feed a tiny portion at various times throughout the day.
Baby Brine Shrimp
Widely regarded as the perfect food for guppy fry, it's been shown that in its hatched state as a free-swimming nauplii, while an excellent food, it is not a as perfect a food as good as decapsulated brine shrimp eggs. Depending on the size of your breeding operation, daily hatching can be a very time consuming chore that doesn't offer benefits commensurate with the time and energy required to keep a steady stream of newly hatched BBS at your disposal. The first drawback is the hassle of hatching them on a continual basis. After a while this simply becomes a chore and turns breeding your fish into something more esembling work, than the fun you would rather it felt like.
Decapsulated (Non-Hatching) Brine Shrimp Eggs
This is my particular food of choice. In my fish room and is used as the primary food, for all of my fish, whether it be livebearers, Cory cats, angelfish - or any other species. I would guesstimate that this food comprises upwards of 75% of the diet of all my fish. It has maximum nutritional value, ease of use, long shelf life (if stored properly) and yields the best results to growing your fry as quickly as possible. Many people believe that one of the reasons to use live BBS over just using the eggs is to trigger the 'attack' response in the guppy fry. This subject is debatable and poses very little benefit in the feeding of most aquarium fish, including guppies.
Advantages of Using Decapsulated Brine Shrimp Eggs - Source: BrineShrimpDirect.com
Even if you plan on hatching your shrimp it is still preferable to use decapsulated eggs to do so.
For one, cyst shells are not introduced into the culture tanks. When hatching normal cysts, the complete separation of brine shrimp nauplii from their shells is not always possible. Unhatched cysts and empty shells can cause mortalities in fish fry, as pieces of the shell or chorion can be lodged in the digestive tract of the fish.
In some cases, improved hatching percentages (by as much as 10%) can also be achieved from using decapsulated cysts. This is because less energy is required for the embryo to "burst" through the thin hatching membrane surrounding the embryo.
The decapsulated eggs are also thoroughly disinfected, thereby reducing the bacterial load of the hatching medium during incubation.
Lastly, the unhatched cysts (following incubation) are still edible and easily digestible by your fish. In fact, the energy content found in unhatched brine shrimp cysts is higher than that of a hatched, live baby brine shrimp. This is a very valuable course of action when brine shrimp cyst hatching quality is poor.