Basic KilliFacts by Dan Frase

In the last issue we looked at the origins of the term killifish and briefly covered their current classification. Now let's have a go at the more important topic of keeping the little beasties happy. To keep killies happy you must, of course, keep them from jumping out of their containers, and also provide them with a dark substrate and places to hide, and give them a water chemistry suited to their individual needs.

Many killies are in the habit of jumping out of uncovered tanks, especially if they're not pleased with their tank conditions of water quality. So it is important to keep their tanks covered just in case they get a notion to commit fishy suicide. An alternative way to prevent their desire to become floor crispies is to lower the water level in their tanks around three inches or so and use floating plants like watersprite. This has the added advantage of providing the fish with some sense of security, and the fish will use the plants to hide and spawn in. Also useful in killie tanks is the familiar spawning mop. (Ed. note: Look on page to see how they are made) Made from synthetic yarn (usually Orlon or Nylon), they are often the only hiding place for killies in breeding tanks.

Another way to provide killies, or any fish for they matter, with a sense of security is to use dark gravel in their tanks. I prefer to use darn natural gravel (because it's cheap), and I even use a quarter of an inch layer of it in gallon sized breeding bowls. Not only does it help relax the fish, it also gives nitrifying bacteria a place to call home which can be beneficial if live foods aren't used. Like most killie keepers, I have my own recipe for killie water. This is only meant for use with those killies that can stand our moderately hard and slightly alkaline Northeastern Ohio ground water since, after all, there are over 600 species of killies and their natural water conditions range from extremely soft and acidic jungle stream to brief jaunts into sea water. Therefore, any generalizations about water conditions for killies are dangerous at best and should not take the place of the old reliable: read a little! However, since I mentioned it, here's my water recipe for killies that can be keep in our Northeastern Ohio water.

To each gallon add: 1 drop dechlorinator 1 or 2 drops Aquari-sol 1 teaspoon salt 1 small squirt Blackwater extract The first two aren't really necessary. I use dechlorinator since I don't always properly age my water. This isn't a good idea though, since in times of drought and in the winter, waterline pressures go up and more gasses are dissolved in the tap water. When this water is added to an aquarium it may cause gas bubble disease which certain killies, Aphyosemions in particular, are susceptible. The Aquari-sol is added for prevention of parasites and fungus. Salt is added to all killie tanks. It doesn't effect water hardness and all killies (as far as I know) can tolerate it. It's used primarily to prevent velvet. a parasite that most killies are susceptible. For Nothobranchius species the amount of salt sold be doubled since they are especially susceptible to velvet.

Any kind of salt can be used, but rock salt should be avoided since it may contain dirt and impurities. Noniodized table salt can be used, but there is evidence that fish can develop goiters if insufficent iodine is in their water (1:60), so iodized salt should probably be used. This is contrary to the popular belief that iodized salt to poisonous to fish, but I have used it without apparent adverse effects on my fish. Blackwater Extract is basically peat moss extract with a few vitamins and minerals added. It is sold as a spawning aid, but peat extract has other used. It is known to reduce the number of belly slider fry that occur in hatches of peat spawning killies by helping in the development of their swim bladder mechanism (2:15). Jorgen Scheel believed that some killies could not reach sexual maturity without the presence of the humic acids contained in peat extract. The reason for this is that the best conditions for killie fry to grow occur when their water is full of organic matter, such as leaves and bark, which infusoria feed on, providing the fry with a source of food. The decaying leaves would also increase the concentration of humic acids which, according to Scheel, would cause fully grown fish to mature and breed at a time when the newborn fish could benefit most from the increase d food supply. I don't know if this is true, but it seems to be a good enough reason to add a little (too much can be deadly) peat extract to the water.

That's it for now. Next time we'll continue with more killie basics. Until then; try to keep your killies happy! References: 1. Aquarium Online. Aquarium Fish Magazine. Vol. 1, 6:60. 2. Lehmann, Monty. The Blue Lyretail Aphyosemion filamentosum. Freshwater and Marine Aquarium Magazine. Vol. 8, 12:L14-16. Scheel, Jorgen J. Rivulins of the Old World. Tropical Fish Hobbyist Publications, new Jersy. 1968.

Killie Basics Part II by Dan Frase

In keeping with the nature of this column - that is, to clear up some of the commonly held misconceptions concerning the maintenance of killifish, and to introduce this fascinating and diverse group of fishes to those aquarists who would otherwise shy away from them - we're going to take a turn to some seemingly obvious, though all too often misunderstood topics. Probably the most important lessons for beginning killie keepers to learn are how to acclimate killies properly to new surroundings, and what size of tank to use for breeding or raising killies. Failure to understand either of these will almost certainly lead to failure. Most killies seem particularly effected by sudden changes in osmotic pressures created by different concentrations of dissolved mineral matter. Usually, a change from water with a low concentration to water with a high concentration of mineral matter will not have that great of an effect on killies. But a sudden change from a high concentration to a low concentration of dissolved mineral matter may cause a killie's gills to burst, suffocating it (1:25). According to Jim Gasior, a breeder of difficult killies, if the change is drastic enough the fish will literally explode! This isn't to say that killies are delicate. On the contrary; killies are generally hardier than characins or cyprinids. In fact, I regularly give some of my killies 100% water changes. I wouldn't advise anyone to do the same, but it goes to show that if water with a similar salinity is used when changing water there's little need to allow the fish to adjust. When new killies are purchased, or when moving killies from one established tank to another however, they should be acclimated to their new surroundings very slowly. I do this using flat-sided gallon bowls and lengths of airline tubing with shut-off valves attached to one end. First let the bag containing the newly purchased fish float in the chosen tank for five minutes or so to let the temperature of the water in the bag start to adjust to that of the water in the tank. If there's a light over the tank it should be shut off to keep from heating the water in the bag. Then the fish are placed in a gallon bowl with only enough water from the bag to provide a depth of two inches in the bowl. When moving fish from one tank to another, simply place the fish in a bowl containing two inches of water from the tank that they came from. Next the open end of the tubing is place in the chosen tank with a rock bound to it with a rubber band to keep the end below the surface of the water. A shut-off valve is attached to the other end of the tubing, and water is siphoned from the tank to the bowl at the rate of two of three drops per second.

If you mark the initial water level on the side of the bowl with a marker that will write on glass (I use a freezer wrap marker) you'll be able to tell how much water has entered the bowl. I usually allow the bowl to fill to at least three fourths full, and since this takes a couple hours, I find something else to do in the meantime. When enough water has entered the bowl, the tubing is removed and the water is poured through a net and finally the fish are placed in their tank. You never save the water that fish are bagged in since you never know what kinds of nasties accompanied them.

The other often misunderstood topic is what size of tank to use for either breeding or rearing killies. Most of the popular literature on the subject suggests that small containers can be used in both cases, but this approach to keeping killies will almost certainly lead to problems and disappointments. It may be true that some killies bred better in small containers because of the constant proximity of males and females. But you'll find that the sexes have to be separated occasionally for conditioning as egg production decreases and the males become overly aggressive. If you're using small containers, this means that you'll need more of them to separate the fish in, and if you keep as many killies as I do you'll soon run out of room. A better way to breed killies is to keep the pairs or trios in 2 1/2 to 10 gallon tanks appropriately furnished with dark gravel, floating plants, and sponge filters. In this type of setup there won't be as much aggression, growth won't be stunted, and the fish will be less susceptible to disease since water quality is easier to maintain in larger containers. Egg production won't be as good, but you'll still get more eggs than you'll know what to do with.

There are also those killies that should never be kept in small containers because of an increased metabolism such as annual killies or lampeye type killies, or because of territorial tendencies like those shown by pupfish type killies. Annual killies won't grow or breed well in small containers, and lampeyes are all pelagic (open water) fishes that need a lot of room to swim around. Male pupfishes, especially those of the genus Cyprinodon, will establish and defend territories. So only one male, along with several females, can be kept in a ten gallon tank. Another mistake commonly made is to use small containers for the rearing of killie fry. The popular literature suggests using covered sweater boxes for the first few days of weeks after killie fry are hatched to let them reach a suitable size before being placed in a rearing tank. This is standard procedure with killies, and I also use this method although I prefer to use dishpans because they're cheaper than sweater boxes and usually hold more water. The problems associated with the uses of these containers are that some people get the mistaken impression that killies can be raised to maturity or at least to a saleable size in them. The water quality in them is almost impossible to maintain, owing to the lack of filtration and constant overfeeding. Killie fry should not be kept in these containers for more than a week or two at the most, even if the water is changed every day or every other day as is recommended. Otherwise, their growth will be permanently stunted and they may die from the typically poor water quality if they can't find another way out. It's amazing to see how far a quarter inch killie can jump to get out of these death traps! I'd take this as an obvious indication that killies aren't happy in small containers. That's enough for now. Next time we'll start to cover the methods used to breed killies. Until then; remember to spend a little time acclimating your killies and to give them enough room. For as much money as you'll spend on them they deserve it!

References: 1. Scheel, Jorger J. Rivulins of the Old World. Tropical Fish Hobbyist Publications, New Jersey . 1975.