Tim Addis BKA 4-4

timaddis@killifish.force9.co.uk

All Photo's by the author unless otherwise stated.

In This Issue :-

What stimulates fish to breed? // Aplocheilus panchax Exame // Fp. mirabilis intermittens Etuku // Fp. gardneri nigerianus Gold forms // Holiday feeding.

What stimulates a species to reproduce? Homo sapiens do very nicely on 5 pints followed by a curry on a Saturday night. But what stimulates our killies & what can we do to induce them to spawn?

No.1.. Pairing ratio. Do you have a pair or trio? A trio comprising 2 females can prove difficult as the redundant female can harass a spawning or eat eggs layed.

No.2.. Water. Killies prefer soft water on the acid side. If you use tap water on the hard side this could be your problem. Try rainwater. If this is collected off glass or plastic it should be as good as it gets unless you are in an area where airborne pollutants might affect your water. It’s not a bad idea to do a pH check first to make sure it’s not too acid & buffer it up if needed.

No.3.. Temperature. We all assume our fish come from warm climates. Killifish are the most diverse group of fish known. Ranging from the Argentinian pampas where climate is similar to the UK to the Pupfish of USA where temperature exceeds our scale of what a fish can live in. Many mountain Aphyosemion for example only do well at 68’F or below.

No.4.. pH. In nature organic waste breaks down and releases trace elements and tannins which are beneficial to fish. If fish are kept in an alkaline environment and slowly introduced to an acid environment this can induce spawning.

No.5.. Light. Always overlooked but this can be a trigger to spawn. Natural daylight is a great spawning inducer.

No.6.. Water flow. Many Aphyosemion are found in fast flowing streams. To induce this scenario turn up the airline to produce a water flow.

No.7.. Food. Mosquito larvae are well known as a good food to induce spawning. I consider them to be the best conditioning food. Bloodworm is also good, as well as roe. Roe is a bit hit and miss but is worth considering in conditioning a pair for breeding. Remove all uneaten pieces.

No.8.. Barometric Pressure. Another overlooked attribute to spawning and a controversial one. Little has been written about this. Few (including myself) believe this influences the onset of breeding where a sudden drop in barometric pressure occurs. This is easily observed by recording egg production daily. Observe production prior to a thunder storm and just after and draw your own conclusions.

No.9.. Are they ready. We have all had fully grown fish we could not induce to breed.I have found that A. poliaki for example which we raised on from a wild import were fully grown for months before starting to lay. F2 fish from this collection are showing the same pattern. I’m sure we have all found this sort of thing in the past. Perhaps the moral is not to give up on a species but to keep trying different things and if all else fails keep them in good condition and have patience.

Daphnia. How has this years collection been. My Spring pond has been going well through to late July where it normally dies back around June. My late summer pond has produced very little this year but in the spring it contained a lot of glass larvae. Alan provided some large Daphnia (possibly magna) earlier in the summer months which has produced a good crop of food to fill the gap. Mosquito larva is in good supply this year which has been fed to the fish at least twice a week. The Ps. annulatus really go for them as they tend to hang out under floating leaves.

As promised in a past issue I have included photos just back from developing. I don’t yet have a digital camera but still have the utmost confidence in my trusty old A1.

Aplocheilus panchax was the first killie I kept as it was imported in quantity when I served my apprentiship in the fish trade in 1969. At the time all I could find was these and Jordanella floridae. I was pleasantly surprised when Alan presented me with a pair he bid for at our Midland auction. As you can see by the photo’ the outer (marginal and sub-marginal) bands go all round the caudal fin instead of the usually imported variety where these bands appear at the upper and lower edges.