It is easy to keep the majority of livebearers on the prepared foodstuffs that are widely available for tropical fish, although there are now specific diets available for them too. Flake food is to be recommended, as it appeals to the natural feeding instincts of this group of fish by floating at the surface.
Mouthparts of livebearers fish
Although it may not be especially apparent in many cases, livebearers do have teeth in their jaws that also extend to the roof of the mouth. Their upturned lower jaw is relatively flexible and is set against the straight upper jaw, so they can rasp algae off a rock without great difficulty.
The mouth itself is quite small and restricts the size of their prey. The lips are often slightly swollen, particularly in the case of those species that graze regularly on algae, helping to cushion them as their jaws rub on the rockwork colonized by these plants.
However, exceptions to this basic arrangement do occur, noticeably in the case of the pike minnow (Belonesox belizanus) and members of the halfbeak family (Hemirhamphidae). Pike minnows are the most predatory of all livebearers, and as such are equipped with much longer, tooth-filled jaws that enable them to seize and swallow their prey effectively.
The digestive tract and diet
The actual digestive system of livebearers is not significantly different from our own. Food passes through the mouth and into the stomach, before proceeding from here down the intestinal tract, where the nutrients are absorbed into the body. The relatively long structure of their digestive system is an indication that most livebearers are omnivores although vegetable matter features quite prominently in their diet.
While feeding livebearers is generally straightforward, thanks partly to the development of specially formulated products, it is also important for their diet to be supplemented with natural foods. This helps to compensate for what may otherwise be a diet containing an excessively high amount of protein. Too much protein will be not be used to create muscle but instead converted to fat in the body, causing the fish to lose condition, and this, in turn, may affect their breeding performance.
The upturned mouth of most livebearers also gives an important insight into their feeding behavior, revealing that they seek food in the upper reaches of the aquarium rather than hunting around the base for it. This means that flaked food is a particularly suitable feeding option for this group since it floats readily on the water’s surface.
If you offer no more than a pinch or so at a time, the livebearers will eat it up before it can sink to the floor and consequently pollute the aquarium. Any uneaten food left at the bottom can easily accumulate around rockwork and another tank décor, where it may be hard to see. It can then easily cause a sudden and serious deterioration in water quality thanks to its effect on the filtration system.
Within an aquarium, surface currents from the filtration system may sweep the food away too quickly. In such cases, it can be useful to have a feeding ring, which keeps the food in one place and allows the fish to find it easily. Always feed the livebearers cautiously at first, just offering them a small pinch of flaked food at a time.
This is necessary partly because the filtration system in a newly established tank is not functioning at maximum efficiency, and so any food left over is a particular threat to the fishes’ well-being.
It also takes the fish a few days to settle into their new surroundings, especially after the stress of the journey home, and this can affect their appetites. Before long, you will know almost exactly how much food to offer them in order to ensure that they have enough to eat without any waste.
Greenstuff (Like algae)
Since it takes time for green algae to grow in the aquarium, it is important to supplement the diet of the tank occupants with other sources of plant food. This is required not just for the health of the fish, but also keeps them from nibbling the new plants in the aquarium and so allows them to become established.
You may want to offer fresh greenstuff for this purpose, particularly if you grow vegetables such as spinach or lettuce in your garden and these are free from chemical sprays that could otherwise be seriously harmful to the fish. The livebearers are able to nibble pieces off these leaves, especially if they are supported in a plastic clamp attached within the aquarium.
This also makes it easy to replenish the leaves as necessary, before they begin to rot away. Alternatively, however, you can dice the leaves into very small pieces and drop them into a feeding ring. The ring helps to prevent them from drifting off around the tank, although ultimately the pieces will sink if they are not eaten.
Another useful supplement to the diet of many livebearers is frozen peas, which should be thawed before being dropped into the aquarium. They must be used with particular care, however, to avoid any accumulation of uneaten peas, and it is also a good idea to remove the outer shell as this is indigestible. Fresh peas can be equally palatable, although they can be made more digestible if they are parboiled first and allowed to cool.
The prepared foods based on Spirulina algae that are now available are also popular with livebearers. Special algal wafers offer another means of supplementing the vegetable component of the diet and are appreciated by mollies in particular. Some flaked foods contain a higher proportion of vegetable matter than others.
The prominent reddish-orange coloration of livebearers such as swordtails and platies (Xiphophorus spp.), not to mention guppies, can be influenced by their diet, particularly by a chemical known as carotene.
Breeders have traditionally used foods that are naturally rich in this coloring agent to supplement the diet of their fish, usually carrot. The carrot needs to be boiled in a small volume of water, left to cool, and then chopped into very small pieces for the fish. Only a small amount is required.
As an alternative, there are special color foods on the market suitable for such fish, in the form of flake. These include specific guppy diets. Another natural way to improve the reddish coloration of some livebearers is by offering them live foods, notably daphnia.
Although they are sometimes confusingly known as water fleas, Daphnia are in fact crustaceans and not fleas at all. They feed on tiny microbes in the water, which are sources of carotene, and hence can supply color to a diet. Feeding live foods, especially those of aquatic origin, is not without its dangers, particularly if they are collected from the wild.
In the case of daphnia, other aquatic organisms present in the water in which the crustaceans have been collected can be hazardous to livebearers, especially fry, even to the extent of preying on them. There is also a significant risk of introducing diseases to the aquarium through this water.
Fresh aquatic live foods need to be purchased frequently as storage can present problems, and so you must be close to an aquatic store in order to obtain regular supplies. Even so, they have a short shelf life. When buying daphnia, always check the bag to ensure that the majority is alive, swimming around rather than lying dead at the bottom.
A long-term solution to obtaining a constant, fresh supply of daphnia is to set up your own breeding colony outdoors in a spare tank. All you need to do is allow the tank to fill with rainwater and then introduce the daphnia here.
During the warmer months of the year, they should breed readily without problems, and you can net them using a fine sieve, transferring them to the aquarium. Only transfer relatively small numbers, which the livebearers should eat readily; otherwise, the daphnia may start dying in the aquarium, thereby affecting the water quality.
Although they are very popular with livebearers, tubifex worms are even more hazardous than daphnia because of their origins. They inhabit stretches of water where there is high organic contamination, such as in the vicinity of sewage outflows.
Tubifex, therefore, need to be viewed with caution, although they can be cleaned over a period of time by being left in a jar or tray under a dripping faucet. These worms cling together in such surroundings, forming a mat, and if they are not kept in running water their tank must be refreshed at least two or even three times a day. It is also important to store them in a cool, shaded spot outdoors, as they will soon die if exposed to bright sun.
Small chunks of the worms can be offered to the livebearers via a special tubifex feeder. This needs to be fixed onto the side of the aquarium just below the water level and is usually held in place here by a rubber sucker. The livebearers cluster around the feeder, taking the worms out of it. The feeder prevents the worms from invading the gravel, where they split up and so are less likely to be eaten by the fish.
Prepared live foods
Partly because of fears over the health problems that can arise through the use of tubifex and other live foods, and also because of difficulties in their supply, alternative sources of invertebrate foods have now been created for the fishkeeping market.
These include frozen live foods, which are supplied in small sachets that need to be stored in a freezer and thawed prior to use. If you only have a single tank of livebearers, to save waste it is possible to cut slivers off a frozen block with a sharp knife rather than thawing the whole lot. Frozen foods are relatively expensive, but the fish usually eat them.
Gamma irradiation, as used to sterilize hospital equipment, is applied to this type of fish food. This eliminates any harmful bacteria and other microbes, so making the food much safer than if it was fed in an unprocessed state.
Freeze-dried live foods offer another possibility. These are sold in tubs and have no special storage needs, other than that they must be kept dry. This process entails freezing the live food initially, and then removing all the water by drying rather than heating it.
The resulting foods retain their smell and flavor, so their palatability is not significantly affected. A wide range of items is available in this form, including tubifex, but avoid those that are likely to be too large for livebearers, such as river shrimp.
The latest innovation in the field of prepared live foods comes in the form of individual sterilized sachets, which allow you to determine just how much food to give your fish. The sachets do not need to be refrigerated, and the jellylike consistency of such products contains additional vitamins and minerals. Daphnia and blood-worm are now being sold in this form.
The size of live foods is a particular issue as far as the fry of livebearers is concerned. In order to meet their protein requirements and ensure healthy growth, the fry requires a relatively higher proportion of live food in their diet. Small daphnia can be used for this purpose, but many breeders prefer to supplement the food intake of young livebearers with brine shrimp nauplii instead, as well as with prepared foods.
As their name suggests, brine shrimp (Artemia salina) often inhabit shallow saltwater lagoons, which are prone to drying out. They produce eggs, which are simply deposited in the substrate, from where they are harvested. They are then packed and sold in airtight containers to exclude moisture.
There are various ways in which the brine shrimp eggs can be hatched, and special kits are marketed for this purpose. Basically, all you need is a large bottle or similar container that can be kept aerated, and some marine salt to add to the water in which the larval brine shrimp, known as nauplii, will hatch. The water should be kept at a temperature of around 77°F (25°C); hatching takes place after about 24 hours.
The nauplii can then be sieved out of the solution and transferred to the aquarium. Care needs to be taken to prevent the fry from eating the eggshells of the brine shrimps because these can cause a fatal blockage in their intestines. It may be safer simply to obtain shell-less eggs for hatching purposes.
Terrestrial live foods
Other live foods can successfully be cultured in the home, and also represent no threat to the livebearer’s health through introducing aquatic diseases or parasites to the aquarium. A variety of small worms can be obtained in the form of starter cultures.
These include micro worms (Panagrellus silusiae), as well as white worms (Enchytraeus albidus), and grindalworms (E. buchholzi). Although they are not all sold by stores, worms of this type are available from live food suppliers that advertise in the fish keeping magazines.
Divide the starter group into smaller colonies. Place these in a plastic container, such as a clean margarine tub, that has been filled with a peat-based substitute, taking care to ensure that this does not dry out.
Place a little bread soaked in milk adjacent to each group to act as a food source. Keep the culture in a relatively warm environment, topping up the food supply as necessary. Within about a month, it should be possible to harvest worms from the colonies for the fish.
In areas where wingless fruit flies (Drosophila) can be bred, these too can make a valuable addition to the diet of livebearers. Commercial kits and feeding media are available for these invertebrates, but a clean jar covered with a muslin top held in place with a rubber band will suffice, along with banana skins as a food source.
Once the young fruit flies have hatched and grown to a reasonable size (usually about two weeks from setting up the culture), they can simply be tipped in small numbers onto the surface of the water in the tank, where they will soon be gobbled up by the fish. Don’t use all the fruit flies at once, as it is useful to have more than one culture available.
A food that was commonly given to livebearers in the past, but is less widely used today, is ox heart. There are fears that the fat level of this food is too high, and so it is a good idea to use only pieces that are visibly free of fat. Ox heart can be particularly useful for the predatory pike minnows (Belonesox belizanus).
Thin wafers can be grated off a frozen piece and dropped into the tank one at a time for these fish. Any leftover meat soon causes a deterioration in the water quality and is likely to make the aquarium smell unpleasant, so use an aquarium cleaner to lift out any remains without delay once it is clear that the fish have lost interest.
In conclusion – varying the diet
There are clearly a number of feeding options when it comes to catering for livebearers. While it may be tempting to rely on prepared foods because they contain all the necessary ingredients to ensure the fish should stay healthy, do try to supply the livebearers regularly with other items to supplement their basic diet.
In the wild, the fish are likely to have access to a range of different types of food, and this may vary through the year. Greenstuff adds to the level of fiber in a fish’s diet and can help to prevent obesity, which means that not only is it likely to live longer but also have a higher chance of breeding successfully.
Live food has proved to be a useful breeding trigger, especially for those species that tend not to spawn so frequently in aquarium surroundings. It can also have beneficial effects on the coloration of the fish and their growth.