Page 67 - Koi Net - On-Line Koi Magazine - Issue 94
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To filter a 500 gallon tank my personal recommendation feeding can start slowly, building up over a period of a
would be to use something like an Evolution Aqua week or two to allow the filtration system to adjust to
EazyPod, which is designed to cope with a 2,000 gallon the new stocking levels. During any temperature
pond (maximum) and will therefore be better able to ramping or after initial treatments, feeding should be
cope with unusual stresses that it will be placed under. stopped for 24 to 48 hours and again introduced slowly
This should be used with a pump that will turn the pond after this time. It is important to monitor the water
volume over in a period of 1 to 2 hours. The UV should parameters particularly the ammonia and nitrite levels.
be a minimum of 30 watts, with a 40 litre per minute air Regular water changes are essential at a rate of
pump providing aeration to the pond. There are several minimum 10% to 15% per week. Ideally the quarantine
ready made packages on the market and as long as period should last a minimum of 6 to 8 weeks and at
you can find one that meets as near as possible these least until you are entirely confident that the fish are
requirements you should be fine. If you have the skills happy and healthy. Temperature ramping should be
to make your own quarantine system, you could build done as a precaution but any other medications for
something tailored to your own personal needs that can external parasites should only be used if they are
fit into the space that you have available and should necessary. If you add new Koi during the quarantine
only cost a few hundred pounds. period of existing Koi, you will have to start the whole
process again so it’s best to avoid doing this if you can.
Tap water should, ideally, always be passed through a
dechlorinator before it goes into a pond with fish in it The body language of your fish can be the first
since tap water can contain high levels of chlorine or indication of any problems. A Koi that is feeling unwell
other chemicals which can harm the fish or filter. The is likely to leave the shoal and hang around on its own.
ideal water quality parameters would be undetectable The first signs of a problem are often one or more fins
ammonia and nitrite levels (below 0.05 when using a held tight to the body and the dorsal fin down. The fish
digital meter) and nitrate levels of less than 10 ppm with might also start breathing heavily. This can be hard to
pH in the region of between 7.5 and 8. This is what see as it can be mistaken for chewing, so observation
would be ideal in any pond. must be carried out at a period of time when the fish
aren’t being fed. The fish might tend to sit on the
Once your new fish have been introduced to your bottom, again with its fins in – this is a sign of stress. If
quarantine system, a skin scrape should be taken to it sits on the bottom with its fins out, it could be a swim
identify if any external parasites are present. If any bladder problem or cold water temperatures. Flicking
are found, they can be treated accordingly. The and flashing is a sign of external parasites, also the fish
temperature of the quarantine system should be might shake its pectoral or pelvic fins or twitch its
roughly the same as the temperature that the dorsal fin in irritation. At the first sign of any irritation a
purchased fish were kept in. As soon as the fish has skin scrape should be taken immediately to identify any
been introduced into the quarantine system, the external parasite. Excess mucus production, or velvet
temperature should be raised to (or lowered) and held sheen to the skin, is a sign that things have gone a little
at 15ºC/16ºC for 24 hours and then raised to a bit too far and treatment is urgently required. If after
minimum of 23ºC (maximum 27ºC) over the next three several scrapes have been taken and no parasites
days and held for three weeks. The temperature should seen, then the problem could be environmental such as
then be dropped back down to 15ºC/16ºC for another poor water quality or untreated/contaminated tap water
24 hours and again raised back up to the same entering the pond. It could also mean that there is a
temperature as before (23ºC to 27ºC) and held for more serious problem which could be bacterial or viral.
another two weeks. The intention with this process is to The signs would be fraying of the fins, open sores or
deliberately stress the fish in order to bring on an bruising, reddening of the skin and visible blood
outbreak of KHV if the virus is dormant in any of your vessels, raised scales and bulging eyes. If the gills are
new fish. Once the temperature has been raised,
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