Hope you can help me I have a problem with one of my fish.
Pond size = 1,250 gallons
2 x foam filters each takes 17?x11? filters & are 12? deep . 2 x pumps returning 1,400 gallons via a waterchute per hour.
Tank set up for 5 years
pH,= 8.5. Ammonia,=.1 NitrIte, = .1+ NitrAte,= 25 Phosphate,= ? Water temperature = 10c
33% water change 3 weeks ago. Heavy rain caused pond to flow over.
A list of all the inhabitants? Mix of 15 goldfish & Shibunkins plus fry. Koi 4 x New + 3 last year.
When did you last add fish, plants, ornaments or other tank equipment? New filters 3 weeks ago, aereation pump & airstones early April, 4 x koi early April.
Have you added any medication? Just bio start recently, Eradick & Bacterad late March early April.
Problem: 1 of the Koi I have had for just over 12 months is very lethargic, it actually looks dull & ill. It has grown from around 3 inches to around 10 inches in the last 12 months, but has always looked a bit dull, grey. I?ve separated it into a smaller tank but have no idea how to treat it. No obvious sign of infection disease or damage. Fish are generally much less lively this year than previously. Nitrate has risen to 25 from 10 over past two weeks, think maybe because fish are eating more yet plants not growing. Hope you have some advice. Thanks, Karl
Hi, welcome to FK sorry to hear things aren't so good for your koi though. When you say you changed the filters do you mean you swapped out all the media for new? You mentioned an ammonia and nitrite reading so it looks as if the pond is going through a cycle for some reason, ammonia and nitrite should ideally be 0 readings so it implies something as affected the filter bacteria and reduced the colony so it can no longer cope with the waste the fish are producing.
Has the fish grown at a similar rate to the others?
With the heavy rainfall is it possible that some pollutants have entered the pond somehow? You haven't been using weedkiller or anything nearby which could have got washed in with the rainfall? The temperatures have been quite low round here, if it's been similar where you are I wonder if this explains the lower activity levels in general?
Simply swapped foam filters, leaving an old one on top for a week to allow bacteria to spread. All fish seem to grow well, am amazed at how fast they grow. Pond is partly raised 3ft below ground, 1ft 6ins above and no chemicals used nearby. I'm thinking that rain & cold weather might be the cause of most problems I'm having. My pond has only just got to 10c-11c, yet I read of others with pond temperatures of around 18c!! Last year levels were perfect & that's why I introduced a few koi. Water brimming over the top of the pond because of rain. The rain is pretty grubby, lots of particles in it. Thinking of giving the pond a dose of Bacterad, but concerned that it might further cock up the bio system. All the best, Karl.
If you took out the whole of the old filter media after a week i'd guess the bacterial colony has taken a dive and will take a while to get back up to speed, especially with it being a little colder. Filter bacteria don't move voluntarily, they establish enough of a colony to deal with the level of waste available (assuming there's enough media to house them all). They won't migrate to new media if there is adequate food and suitable conditions for them on the old stuff, if that makes sense. Ideally you need to do a gradual swap, by removing bits of the old media every now and then the colony will take a slight knock and then increase in numbers and be forced to colonise the new media You could get some Seachem Prime, I believe you can get a pond strength one, but if not then 5ml treats 200l for normal dechlorination but you can use up to 5x the normal dose to detox ammonia and nitrite as a short term measure
Do you have any pond salt? 1 gram per litre of water will counter any effects of nitrite poisoning and help the fish feel a lot better Nitrite binds with the blood and stops oxygen binding with the blood, salt has a chemical reaction with nitrite that prevents this