Foods & Feeding Killifish
Killes prefer not to eat dry foods. While this blanket statement is strong and not necessarily accurate, there is little doubt that to succeed with these fish, live foods supplemented with some frozen foods are necessary. Most species will ignore, or at the very least, spit out most dry foods. Over time, some may take the dry offerings if it is the only food available, but hobbyists tend to find limited success with growth rates and breeding.
Because of the high rate of metabolism of some species, particularly annuals, it is important to feed the fish a minimum of two times a day. To obtain the optimum growth rate and size, three small feedings a day of a variety of live and frozen foods is recommended. Feeding fry will be covered in a separate section.
Brine Shrimp – Newly hatched Artemia is the killifish hobby’s single most important food source. Artemia are fed to all ages and sizes of the fish on a daily basis by most hobbyists. As a source of nutrition, it should be fed within 24 hours of hatching to provide the optimum amount of the essential minerals and vitamins. Once past the 24 hour mark, the nutritional value of the Artemia begins to degrade without supplemental nutrients added to the brine shrimp container.
Commercial operations enhance the Artemia nauplii with emulsified fish oils containing HUFAs (Highly Unsaturated Fatty Acids) and began the practice in the 1990s. According to the reports, the enhanced brine shrimp has allowed for the culturing of several species of marine fish. There is some question whether or not freshwater fish need or are affected by the added nutrition.
It is very important to note, fish fed exclusively on Artemia will not receive all of the essential nutrition necessary to remain healthy throughout their lives and it has been reported that some of the results include lowered growth rates, decreased reproduction capability and juvenile weakness and death as they near maturity. For this reason, breeders may wish to add supplements to the newly hatched Artemia. Several commercial brine shrimp companies offer HUFA enhanced concentrates to add to the hatching process for BBS. At 77-80 degrees F., Artemia hatch 18-22 hours after being added to water. Immediately after hatching, the nauplii remain within the hatching membrane and absorb the remainder of the yolk. This stage takes a few hours before the BBS emerge. Artemia are filter feeders, but need to molt before they are able to begin feeding. This occurs around 12 hours (again at 77-80F) following the initial hatch. With this information in mind, it appears a feeding rotation of 48 hours is a good choice if using supplements to enhance the food value.
In addition, although discussed later, additional foods such as microworms, Walter worms and daphnia are good alternate sources of nutrition for juvenile fish.
The hatching process is fairly straightforward. There are a variety of hatching techniques and containers, ranging from elaborately constructed systems to very simple bottle and jar methods. However, all styles follow the same basic concepts – a moderate salt solution and heavy aeration.
A simple, yet effective hatching system can be created simply using a 1-gallon container such as wide-mouth plastic or glass pickle jars. Make sure you are able to find a container with a plastic cover. Drill/cut a small hole in the cover large enough for airline tubing to pass through and a second small hole to bleed off the air that bubbles through the water. Insert an airline extender through the hole and attach the air hose from the source to the outside. Add a short piece of air hose to the inner part of the connector and cut it to reach to just above the bottom of the bottle or jar. Because salt will block the line, you will need a removable section to rinse it each time you change the culture.
Alternatively, a 2-liter soda bottle can be used. There is a small stand specifically designed for this option that can be purchased at many local fish stores. The bottom of the bottle is cut and the top attaches to a cap with an attachment for the hose. The system is inverted, water and salt added and then the brine shrimp eggs.
There are various suggestions about the salt content necessary for proper hatching and the wisest course is to follow the directions on the brine shrimp canister. Most commercial companies recommend 25.0 PPT (parts per thousand) or higher or a salinity reading above 1.0183. That being said, most hobbyists develop a simple measuring system adding a set amount of salt per gallon. Approximately ½ cup of salt per gallon will work most of the time.
While some hobbyists are willing to pay the costs at their local fish store for commercial marine salts, most kosher salts will work fine. On a personal note, I have had good success using canning and pickling salt. A few hobbyists will find their local water supply is too soft and need to add a buffer to kosher salts or need to use the marine.
The temperature of the water should be above 77F for optimum hatching. At that temperature, the eggs should hatch in 18-22 hours. As the temperature lowers, the length of time for the eggs to hatch is extended. At 70F it can take up to 48 hours.
When it comes time to harvest the shrimp, the airflow should be shut off and the shrimp should sink to the bottom of the container, while the shells will float to the top. If the shrimp have molted, then they will be free swimming and as they mature to the next molt, they will swim to the top of the stilled water. Depending on the type of system being used, simply drain the nauplii from the container through a brine shrimp net or cheesecloth. The Artemia should be rinsed with fresh water to remove the majority of the salt that may remain and then added to whatever cup, jar or container is used to hold the prepared food for feeding. Techniques to introduce the food to the tanks vary from eyedroppers to turkey basters. It is simply personal choice.
Frozen Brine Shrimp:
Considered a staple in most fishrooms, frozen brine will be taken by Nothos if there are no live foods available. While frozen foods are a viable alternative, Nothos will do far batter in the home aquaria with live foods.
The biggest negative in using frozen brine shrimp is the wasting of leftover food. This can accumulate on the bottom of the tank and lead to fouling of the water. It is highly recommended that excess frozen foods of any type be regularly siphoned out of the tank.
While hobbyists have numerous ways of introducing frozen foods into the tanks, generally a simple method is to take the desired amount of frozen brine and place it into fresh water and allow it to defrost. Using a baster, the food can then be squirted into the tank. The initial motion will attract the fish for feeding. Once Nothos have eaten frown shrimp, they will quickly become comfortable with it and feed easily.
Without a doubt the various types of live worms available to the hobbyist today are a must for breeders. One of the easiest to culture are white worms.
A 50-50 mixture of peat moss and a good soil such as African Violet soil is an excellent base to begin your culture. Add enough water – preferably old, but clean water from from your tanks – to make the mixture moist, but not soaked. This will be the media used to introduce a starter culture.
With white worms, the temperature the culture is maintained is very important. White worms seem to thrive in a temperature range of 45-60 and seem to reproduce extremely well in the low to middle range. Above 60, the culture will survive, but reproduction slows considerably.
There are any number of ways to make sure the hobbyist can keep white worms at optimum temperatures. Many purchase an old refrigerator and modify the temperature range.
This can be done fairly easily by unscrewing (make sure the refrigerator is unplugged or you may have a shockingly revelation) the thermostat control inside the refrigerator. Somewhere on the controller, there generally is a small hole with a tiny screw set inside. This screw regulates the maximum/minimum temperature settings. Simply by adjusting the screw (in most case opening it a bit), the temperature can be set to the range necessary.
Alternatively, killie-keepers who live in regions where there are cool and/or cold winters can do quite well by finding an area (generally in a cellar) where most of the year the temperature rarely reaches 70F. During the majority of year, the area remains cool enough for the cultures to thrive.
Styro boxes make decwnt containers for culturing white worms. I place them in a fairly dark area of my cellar outside the fish room. It is generally much cooler in this area.
There are numerous methods to feed the culture, but one of the easiest is to simply use commercially available mashed potato flakes. Even regularly (2-3 times a week) placing a small pile of the dry flakes on top of the culture will work. The flakes quickly draw the water from the soil and become fully moist . The worms will eat it in this fashion quite readily. Perhaps a better method, however, is to simply make extra potatoes for dinner and use the excess. By adding some form of liquid nutrients to the potatos may well enhance the worms themselves. At times, varying the diet with bread soaked in yeast water or even dried cat food may help.
Placing a piece of glass or plastic over the feeding area has often been suggested by hobbyists. Some hobbyists are able more easily harvest the worms from the glass cover. While there is no reason not to do this, there is also nothing necessarily gained.
Some hobbyist, however, do place the food on top of the glass or plastic which draws the worms out of the soil to feed and makes it easier to clean them. For the most part, without using the cover method, the worms gather around the edge of the food and are easily removed with little or no soil.
It is necessary to wash the worms before introducing them to the fish tanks. Simply add water to the feeding container and agitate it strongly. The use of a turkey baster squeezing water in and out is an excellent technique. Give the worms a moment to settle down to the bottom of the container and pour off the water. Repeat a couple times, then finally add water you can introduce to your tanks. Using a baster or a similar method, simply feed the fish directly.
Another good live food that is relatively easy to culture is Daphnia. These small copepods can be found is still waters in most temperate regions of the world, particularly during the early spring when there are often huge blooms. As a survival mechanism, daphnia have evolved two ways of reproduction – in cold temperatures, they produce egg cysts similar to brine shrimp to weather frozen conditions, but at warmer temperatures, they produce ‘live’ young.
Culturing Daphnia is not difficult by any means. A thirty-gallon plastic container such as “Rubbermade” can be used. While there is some success in using aquariums, it seems the culture does better in a container that does not have clear sides. Add a small amount of air, only enough to break the surface, with an airstone and also consider adding some plants such as Java Moss. To this introduce a starter culture.
Rubbermaid 30-gallon bins are perfect for raiseing Daphnia. Maintaining several cultures will ensure a continous source of this crustacean
Careful feeding is an absolute. It is easy to overfeed and kill the daphnia culture. Many hobbyists use yeast as a base food and it certainly works. An alternative (and a personal preference) is to use baby food, in particular, sweet potatos. Add a small amount of whatever you choose to feed the daphnia to fresh water and stir it into a cloud. Add enough of this mixture to lightly cloud the container. The daphnia, being filter feeders will feed voraciously and within 1-2 days the water will be crystal clear and it is time to feed again.
It is very important to understand the culture must be harvested regularly or it will crash. A strange phenomenon with daphnia is that if it is not harvested regularly, the daphnia will stop producing and the hobbyist may not be able to maintain the culture. Occasionally, some of the cysts will survive this situation and with a water change and re-emersion, the culture may restart.
Most Notho keepers maintain two or more operating cultures of daphnia, both to provide good, constant feedings as well as protect against crashes. There are several types of daphnia and the related moina available in the hobby.
There are a number of other foods which can be collected or cultured including mosquito larvae, black/tubifex worms and fruit flies. Any and all of these are excellent choices, even if only occasionally and most killies will attack them voraciously. (Use and culturing some of these and other foods will be contained in The Encyclopedia of Killifish (available on Amazon)
For example, the picture to the left is a vinegar eel culture. Use of 50% apple cider vinegar and water works very well. Adding a food source for the eels is as simple and a small piece of appple into the media.