The fry will live only a few days off of their yolk sac and will then need to be fed. I use a plastic eye dropper while the fry are in the tank with their parents to make sure the food gets to them, and so I can put the correct amount, since excess dirties the tank so much. If you feed baby brine shrimp the fry should have full orange colored stomachs. If you use a powdered food, such as First Bites, the fry will develop golden-yellow stomachs. If you do not have means to have live BBS and feed powdered foods, it is important to mix it up in a small cup of water for a few seconds so that all the particles break up and soften to where the new fry can eat it easily. Portions can be small and only what the fry will consume in a few minutes. However, they do need to be fed every three hours if possible.
In my experience with the species, most of the parental deficiencies arise during the free-swimming stage when the parents have difficulty maintaining the cloud of fry, and eventually they would get lost in the tank and snacked on by the other fishes. However, it is worth noting, that Bolivians are known to eat their eggs several times before they have a successful spawn. I prefer to leave the fry with the parents for as long as possible, and then as a last resort, remove the last remaining 20-30 fry and raise them, rather than remove a large group of fry prematurely.
When it is time to remove the fry, I have found the simplest way is to merely siphon the fry out of the tank. If a good number of fry are left with the parents, I like to leave 10-15 behind with the parents. I believe this helps with pair stability and allows for more opportunity to practice their parental skills. For this species, the initial grow out tank does not need to be large, a standard 10 gallon is adequate. I have a routine for this process that has proven to be very successful. I do small water changes on the main tank while the fry have been developing, but I do not vacuum the substrate. So, I fill the grow out tank entirely with water from the main tank, and take caution to maintain the temperature precisely. This allows for the least shock to the fry, and offers an opportunity to thoroughly clean the adult's tank. I equip my grow out tank with a heater, filter, small air pump driven bubbler, and a small clump of java moss and nothing more. Sponge filters work great, but small power filters are fine too, I merely turn the flow down to minimum and cover the intake with mesh, and take care to maintain the water level as to limit the current created by the return. I use bare bottom tanks because of the need for daily cleanings, yes daily.
My standard routine is to siphon out two gallons everyday and clean the bottom while doing so. Using a small diameter hose will keep the flow slow, and allow amble time to clean the entire tank bottom and make it easier to avoid the fry. Take care to adjust the temperature of the incoming water. I believe the species is very sensitive to fluctuations in temperature at this young age, I will restate that 77F is ideal. During these cleanings, the water volume exchanged is not great, but the debris and uneaten food is kept from accumulating, which allows for the cleanest tank and most stable conditions for the fry. Care should be taken that the NO3 levels do not exceed 5ppm during the first months of development, or significant losses could result. I add the clump of java moss for shelter, and although the fry will not eat it, they will rasp off of it on occasion. I use a small air pump to drive a bubble maker (only when using a small power filter), and use a suction cup mount to place it a few inches below the water surface (to where it is still submerged during maintenance, but as high as possible to limit any current created). Ideally the fry should be fed live baby brine shrimp every three hours; however, I must admit that I have had no difficulties raising the fry entirely on powdered foods such as First Bites. A lot of species cannot adequately eat the particles, but I have not found this to be a problem with this species.
The fry will need to be transferred to a larger grow out tank as needed, I have had success using a 36" tank for grow out of small groups (20-30 fishes), and typically move the fry into this sized tank between 12-16 weeks or age. In this secondary grow out tank; I usually add a sand substrate and some vegetation for shelter. I do still lean on simplicity so the tank is still conducive to cleaning. At this age, the fry do not seem bothered by a lack of shelter, and are quite social. A 6 months of age, my fry will eat from my hand.
The fry grow painstakingly slow, and after 11 weeks may only be 1/2" in length, and after 6 months measure 1 1/4" or less. After the fry are 12 weeks old, you can start crushing up sinking cichlid pellets (or whatever you feed the adults) and start weaning them onto that. I haven't had any trouble with juvenile Bolivian Rams, they have readily accepted all prepared foods offered, and eat eagerly. However, make sure the particles are an appropriate size, as the fry and adults alike; do prefer small, easily consumed morsels. The food will also typically need to sink. Fry will become brave and learn that they can feed from the surface, but it is easier for them if the food sinks readily. I feed the fry small portions, every three hours for the first two months, then three times per day up until the age of 6 months, when I adjust them to two feedings like the adults.
The abdominal spots and facial banding will start to develop around 12 weeks of age, the red lining of the caudal and dorsal fins will develop between 15-20 weeks, and the red in the anal fin shortly thereafter but will not be fully developed until 6 months. The blue in the pelvic fins also develops around 6 months. At this age, the fry are of a sellable size, or large enough to be combined with adults if the tank space allows. The yellow abdomen may not develop until the fish are mature, after 8-10 months.
Poor quality Bolivian Rams are common in the hobby, and deformity is a problem with the species. The reason for this is inbred fish, poor strains from Asian farms, and a lack of wild fish to mix into the breeding lines. Take care to study your fry before dispersing them into the market. Common deformities include bent spines, clamped tails, short bodies, large lips, and curled pectoral fins, if present these will be visible in fry after three months, and usually occur in a low percentage.
Overall, the fry are quite easy to raise, care needs to be given to fluctuations in temperature and Nitrate levels, but otherwise they do not present any problems.