Q I just bought koi fish and they have started to get ill being put in our newly filled pond. It started with dark discoloration, inactivity and lack of appetite. What should I do? Should I separate the sick fish? M Hammond, Didcot

A Your fish are probably falling ill as a result of a build-up of ammonia. Ammonia build-up is caused by fish waste and decaying organic matter (like fish food). In an established pond, one that's been up and running for some time, this waste will be quickly broken down by bacteria present in the water. Because your pond is newly filled there does not yet exist enough of these bacteria to break down harmful ammonia and this is why your fish are sick. What you need to do is:

  • Change half of the water
  • Add pond salt to the water. Any brand will do – just follow the directions on the product label for the proper dosage amount. Pond salt is therapeutic in nature and will help the fish in a few ways. Pond salt is different from sea salt in that it will not significantly raise the saltiness of the water.
  • Cut down on the amount of food being fed. Feed the fish only a small pinch of food once a day or once every other day until ammonia is eliminated.
  • For now, do not clean the filter nor change/clean the filter media as this is where beneficial bacteria set up home.
  • Test the water or have the water tested for levels of ammonia, nitrites and nitrates.
  • Add additional aeration to the water/pond in the form of plants and/or an air pump.

Q My dog Sammy jumped off the bed and when he landed his paw went under him. He started howling, but we were able to calm him and straighten the leg. We splinted it and wrapped it and have him in his cage. At this time I cannot afford a vet bill but want to do the right thing to help him get better. Please give me advice, we really love this dog. S Rose, Abingdon

A You really do need to take him to your vet for pain relief if nothing else.

It is possible he has broken a bone (or bones). This is very painful, and if not treated the bones will not heal properly or could heal in the wrong position – leaving him permanently disabled with constant lameness and possibly arthritis.

It is possible the bones will not heal at all or infection could set in. I would not advise home splints and wrappings unless you have some experience with this, it is all too easy to dress over tightly and then the blood supply can be cut off causing horrible pain and severe tissue damage.

Contact the RSPCA, the PDSA or another animal charity for help with vet fees.

Q I have two male ferrets aged 10 months. One is bigger than the other and the smaller of the two is less active and very slim. They both have excellent appetites and play energetically with each other and us, although it takes the smaller one a little while to get going. Is there anything wrong with the little one? The breeder I got them from did said he was the “runt”. P Smith, Cowley.

A It does sound like he may well be a runt but there is nothing wrong with that as by definition they are smaller than their litter mates so they have to be tough to survive. From your description he is healthy and happy and he may never be big and fat. It would be worth having him checked for parasites like worms, your vet may be happy to analyse a dung sample for worm eggs.

Otherwise, unless there is a deterioration in his health, there is probably no real need to worry.