Running a fishroom can be time consuming, and sometimes there just isn’t enough time. I had quite a lot of eggs of Nothobranchius furzeri from last autumn 2007 , and i’d been keeping them cool (fishroom floor, 20 degrees C) because I knew I wouldn’t have time to raise them until July 2008.

I had 3 bags of Nothobranchius furzeri Gona-Re-Zhou and one of a red strain, Moz 99-4. I’d been checking them on and off; eggs had always been visible, in various states of devlopment. A couple weeks before I was to hatch them, I put them  on a high shelf in my fishroom (28 degrees C).

Day 1: Approximately 220  fry hatched from 4 bags. Very few belly sliders, but a few deformities in the Moz 99-4s. Vast majority of fry are normal and healthy. Fry fed newly hatched artemia immediately.

Day 2: Some fry are moved from the hatching containers to their new tanks. Fry fed newly hatched artemia. Most eat ravenously, though a few, despite no influence of other fry don’t eat. They examine the artemia nauplii, but then just don’t eat, seemingly preferring to go hungry.

Day 3: Remaining fry moved to their tanks. More artemia.

Day 6: The fry are offered (and take) grindal worms for the first time.

Video Clip: Nothobranchius furzeri Gona Re Zhou eating grindal worms (10 days old). Click the the image to go to youtube and play the clip. Note there is a high resolution version (just below the image on youtube, look for the ‘watch in high quality’ link)

Day 10: They are given cyclops and small mosquito larvae. The cyclops are agile and take some catching.

Day 12: Some fish ate cyclopeze when offered, though by no means all. They are still not particularly keen on it.

Video Clip: Nothobranchius furzeri Gona Re Zhou (14 days old) eating Daphnia magna). Click the the image to go to youtube and play the clip. Note there is a high resolution version (just below the image on youtube, look for the ‘watch in high quality’ link)

Day 13: I collected a lot of daphnia and mosquito larvae (including larger ones, see below).

Top: Nothobranchius furzeri Gona Re Zhou examining a mosquito larvae. Bottom: Eating a mosquito larvae.

So that was the first two weeks. They’ve got a little bigger now, and they are always hungry. Still no sign of any colouration to determine which are the males, but some of the larger individuals are clearly male. Keeping them well fed enough to prevent too much canibalism is tricky, and I will be separating them soon into small groups until they sex out.

Its hard to say what your favourite killifish species are… but in my top 5 would have to be Nothobranchius furzeri; i’ve been keeping the Gona-Re-Zhou furzeri on and off for some time now, a long with other Mozambique collections since they became available in 1999.

And what an interesting animal. Furzeri actually holds the record of shortest living vertebrate – you’re pretty lucky if the fish live past 6 months old. Its also one of the longest kept strains in the killifish hobby, having been imported into America once in 1969 – and still going strong almost 40 years later.

It is regarded as one of the more difficult species to maintain long-term, but this need not be the case, if a few simple steps are taken.

It was initially discovered by Richard Furzer and Dr. W. Warne of the (then) Rhodesia Dept. of Agriculture, in the Sazale Pan of the Gona-Re-Zhou game reserve. The reserve had only been open since 1967, being created for the elephants in the area; Gona-Re-Zhou means “place of elephants” in the Shona language.

The original collection was given the name Nothobranchius species U-2 until it was formally described by Jubb in 1971. Nothobranchius orthonotus, (initially designated species U-3), was also present in the same pool.

So why is this species regarded as so tricky? Well there are a number of reasons, in fact common to all annual fish, but exaggerated in N. furzeri

1. The short lifespan, and therefore time in which to collect eggs
2. The fast growth and predatory nature of a few young fish
3. The unpredictable development of eggs

None of these problems are insurmountable with a bit of effort

Problem: Short lifespan

When you hatch a batch of Nothos some fish always outgrow the others. In my experience the quickest growers will always bloom magnificently and die equally quickly. These fish (typically male) reach sexual maturity after a few weeks, and last 3-4 months at most. The more slowly growing individuals take longer to sex out, but will live sinificantly longer than their quick-growing siblings.

Solution: It is essential to make sure that all fish have peat to lay in as soon as they need it

Problem: Predatory nature of young fish

Moreso than other nothos, N. furzeri fish and fry will eat their siblings if they can. In many cases this will be the quicker growing males eating the smaller unsexed fish. This can be a real problem with smaller hatches. If left unchecked it can result in a tank with no female fish.

Solution: Fry should have access to nourishing food at all times (Artemia, grindal worm), the more access they have to food, the less canibalism will occur. Faster growing fish should be separated from the smaller individuals as early as a few days old. Allowing hiding spaces also helps – the rearing tank should be large enough, with clumps of free floating plantation and dim lighting.

Problem: The unpredictable development of eggs

There is little you can do to counter this. Development can take anything between a few weeks, up to several years (though usually less than one year).

Solution: Keep a lot of eggs – don’t distribute too many, but most of all examine the eggs more regularly than with other species- catch them when eyed up and ready! Don’t keep the eggs too warm.