In my post last week I detailed the spawning which finally took place on the night of 17th-18th May and the hatching and development of the fry over the course of the following week – http://nishikigoi.life/2019/05/28/my-spawning-project-underway/.

It’s now 14 days since the fry started to hatch on May 22nd, since then the assessment of the total number of fry just grows and grows as the fry themselves get bigger and more visible around the surface and throughout the whole water column.

What started life as tiny slivers of glass 2 weeks ago are starting to grow and develop quickly.  The transparent bodies are becoming less so.  Signs of the metallic crystals which will define them developing on the skin surface.

2 week old white baby

2 week old white baby

2 week old white baby

2 week old white baby

2 week old white baby

2 week old white baby

2 week old black babies

2 week old black babies

2 week old black baby

2 week old black baby

Towards the end of last week, for no particular reason, and with nothing to suggest there was anything amiss, I decided to do an ammonia test, the first for a week or so.  The fry seemed fine, were feeding well, but were only in reality getting a tiny amount each day compared to what had been being fed to the larger Koi that had resided in the tank pre-spawning.  I was alarmed to get readings of between 0.25mg/l and 0.5mg/l on both the Kusuri and API test kits.  My instant reaction was to undertake a swift series of water changes, refilling with water which had passed through a water purifier.  At the same time I suspended feeding newly hatched brine shrimp concerned this may be a contributory factor, and reduced the dry food significantly – reducing feed to the fry wasn’t not something which was ideal either.

On Saturday morning with the ammonia levels unchanged, despite the equivalent of over 100% of water being flushed through the system, a trip to Manor Koi availed me of some API Ammo Lock.  At £10 per bottle, and with 3 bottles required, with a redose in 48 hours, that was only ever going to be a temporary solution!  As convenient as mail order may be, and it may save a few pennies, nothing beats having a Koi dealer just around the corner – embrace and support your local Koi dealer!

API Ammo Lock

API Ammo Lock

With the Ammo Lock dosed my mind started to puzzle over what seemed a mystery.  I filled and aerated a bucket of water from the purifier.  Lo and behold, therein lay the problem, what I’d been adding to the tank as ‘fresh’ water was carrying with it 0.25mg/l of ammonia.


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A trip back to Manor Koi saw me purchase one of the Evolution Aqua inline water purifiers.  Sadly even at 1/3 gallon per minute flow rate this didn’t have any effect on the chloramine which continued to persist in the aerated bucket test at 0.25mg/l.

As I looked into the issue of dechlorinators further, I was amazed to learn that even many liquid products which claim to make tap water safe by removing chlorine and chloramine still leave the ammonia portion behind.  I’ll be writing more about the challenge of getting rid of chloramine effectively in another post, it seems that in the longer term some kind of water reservoir is going to be required to ensure that a volume of truly ‘safe’ water is at hand as and when required.

Thankfully I could steal sufficient water from the main pond to drop the ammonia down a little in the tank and that, coupled with a bucket filter filled with zeolite (a product I’ve never used in 35 years of fish keeping) seem to have things under control.  Hopefully the Nexus which seems to have dropped behind a bit will pick up and mop up the excess ammonia in the coming days.

The video below filmed yesterday shows the fry feeding in close up.

 


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