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Killifishes – Part 1.

Robert  J. Goldstein

To many newcomers, the term killifish conjures up that gorgeous Blue Gularis in the Innes book, a fish considered remote and unattainable. Take heart!   Hundreds of home aquarists in the USA and overseas breed and distribute Blue Gularis and a hundred other kinds of killifishes to anyone who wants them. You can get almost every species you ever saw in a book or magazine, and others that haven’t yet gotten into the popular literature.

I’m not talking about native Florida Flagfish, Bluefin Killies, Goldenears, Asian Panchax and African Lyretails. They are all available from pet shops. I’m talking about fishes you‘ll never see in pet stores, gorgeous rarities like Argentine and Black Pearlfish and all the kinds of Nothobranchius (“instant fish”) in every flavor imaginable.

Fundulopanchax sjoestedti, the "Blue Gularis"

With this column you’ll find links to important web sites that offer killifishes for sale or trade, photographs, chats, and information from local, national, and international killifish clubs. Newbies are welcome. Old-timers never quit. You don’t need to be a big shot, rich, or know someone important to get fishes you never even expected to see. You’ll see!

Most of us start out with community tanks, and then experience tank-creep as we get into breeding livebearers or cichlids. Then we go through stages tackling harder and harder fishes.

Killies aren’t the easiest or the hardest of fishes to breed. With most fishes, the problem is getting them to spawn (but that’s not true of killies). With other fishes, getting the eggs to hatch is the trick (Bingo!). Once hatched, they’re mostly large enough for live baby brine shrimp, and are easy to raise. Then before you know it, you’ve got killies up the kazoo. You could take them to your local pet shop, but it’s more fun to sell or trade them through the mail to others like yourself.

You’ll need to know two things to get started: how to care for them and how to ship them. Fortunately, killies lend themselves to generalities, so we’ll worry about exceptions later.

Cynolebias boitonei, a South American Annual Killie.

The basics of care are these. Killies are carnivorous, preferring crustaceans, insects and worms. Live foods are best, and frozen foods okay. You can feed dry food to large concentrations of fishes in grow-out tanks, but it’s risky to feed it to pairs in small containers; I never do. 

A pair needs its own gallon jar, covered plastic shoebox, or 2-5 gallon tank. Aeration is optional but beneficial. Water should be neutral and changed regularly, about 25-50% a week, but that’s not mandatory. Many killies thrive in water that would gag a maggot. To protect against the common disease velvet, siphon the bottom of leftovers and maintain some marine or kosher salt in the water (avoid iodized or rock salt).

Live baby brine shrimp are the main food for killies. Don’t buy small packages of brine shrimp eggs at pet shops, as they usually are ruined by humidity and you’ll get little or no hatch. Get on the Internet and purchase 15-oz vacuum-packed cans for best hatch rates. A can could run about $30, varying year to year by supply and demand. Don’t cut corners on brine shrimp eggs. Plan on keeping two hatching jars going at all times, so you can feed from 48 hour hatch times. If you can grow or buy blackworms, daphnia, moina, white worms, grindal worms, Tubifex, microfex, or fruit flies, go for it. You can’t beat live foods. Best frozen foods are bloodworms and brine shrimp. Don’t use freeze-dried foods.

Killies fall into two broad categories. The annuals are killies that lay eggs in the mud during the rainy season. When the dry season starts, their ponds dry out and the eggs remain viable for months, and sometimes years buried in the pond bottom. A period of drought is essential to normal development. If the eggs in mud (or peat moss) are not rather dried out for several months, the eggs will not develop. So drying is required. In nature, when the rainy season comes, the eggs hatch. In captivity, we substitute peat moss for mud, and dry it out to simulate conditions in nature. Annual killies are more difficult to propagate than other killies, are not available from pet stores, have particular demands for hatching water (rainwater or RO water is good), and are sensitive to unusual diseases such as Glugea, which is impossible to treat. Examples of annuals are the Argentine and Black Pearl Fishes (and their relatives) from South America, and the East African genus Nothobranchius. The East Africans do best with salt, but the South Americans seem fine with or without it.

The second group consists of non-annual fishes that spawn in plants (or plant substitutes like spawning mops). Their eggs are water incubated, and hatch in one to three weeks without any special handling. The easiest way to breed these fishes is to put a pair in a tank with lots of non-rooted plants like Hornwort, Water Sprite, Coontail, Nitella, or Java Moss, and then remove the pair to another similar tank two weeks later. Eggs laid on the plants will eventually hatch, and you can raise the babies in that initial tank a long time (to good size) before you need to transfer them to a larger grow-out tank.

For annuals, you need peat moss as a mud substitute, and then harvest it (with the presumed eggs it contains) once or twice a month. After harvest, the peat moss is mostly (but not completely) dried on newspaper, and then packed away in sealed plastic bags in the dark at about 78 degrees. After three to nine months (species differ), you pour the peat moss into a shoebox or small tank and add some RO, DI, distilled, or rainwater. In a pinch, even tap water will give a hatch. After a few hours to a few days, most of the eggs should hatch, and the babies should be ready for live baby brine shrimp. Later, the peat moss is re-dried for a future attempt at hatching sleeper eggs that develop more slowly.

Baby killies eat a lot (their bellies swell), but leftover food can induce diseases like velvet that can rapidly wipe out a whole batch. That’s why after hatching we may add live daphnia or live snails to the fry tank to take up uneaten food and control bacterial blooms that weaken the fry.

Where can we get these live food cultures? Usually from the same people who provide killies. You’ll also find live food culture ads in the backs of aquarium magazines. Everybody who sells live food cultures also provides instructions on maintaining cultures. Your pet store can provide frozen foods.

Now what do all these things cost? Well, I mentioned about $30 for a can of brine shrimp eggs that should last a beginner a year or more. A pair of killifish should be $5-15 plus shipping of (let’s say) $5-7 for priority mail for one to three pairs. Live food cultures will be about $4-5 each (discounts for multiple cultures). Shoeboxes are a buck or two, gallon jars are free from fast-food places like Subway (I always offer a buck each to avoid being a pest), and you don’t need heaters or lights on your containers. Most killifish people have few real tanks other than grow-out tanks (and some guys use big plastic storage bins from Wal-Mart, K-Mart or Ace Hardware instead of tanks).

When you order killies, always discuss the fish you want with the seller to let him know you are new at this, to find out what he recommends and which species you should avoid at this stage, and any special tips he can provide. The seller needs to know where you want them shipped and on what days they should be scheduled to arrive. Do not attempt shipping or receiving during the peak of winter or summer.

A male Cynolebias adolfoi

The fish will arrive in plastic bags, either regular (with a big air space) or without any air space inside specialized Kordon Breathing Bags. All the books recommend floating the fish to equilibrate temperatures. That’s a no-no with Breathing Bags, which should never be floated. Killies are temperature tolerant (not immune but tolerant), so dumping them into their receiving tank without temperature equilibration rarely causes any problems – just do it.

The shipping box will be a nicely sealed Styrofoam container with paper or peanut or bubble wrap packing, and perhaps a heat pad. Dump the pad, but save the shipping box. You probably paid for it (many sellers charge if you don’t return or supply the box), and can use it when you send out your own production for sale or trade.

This should get you started. I’ll get down to specific groups or special topics in future columns. Good luck.  

Internet Killifish Resources:

American Killifish Association
DKG (Germany)
Killie Trader
Killifish Species
Killifish Species
Chat Room


WWM on the Killifishes

Related Articles: Killifishes, Part II- The Nothobranchius Family  by Robert J. Goldstein, Cyprinodontid Fishes, Aplocheilids, Rivuline FishesAphanius: European Killifish for Ambitious Aquarists by Matt Ford,

Related FAQs: Pupfishes, Aplocheilid Fishes, Killifishes



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