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What's Wrong with my Fish?

21st Nov 2019

What’s wrong with my fish?

This is something we get asked quite a lot here at Bradshaws. It can be really concerning if you notice a change in behaviour or strange marks on your fish, and it could be due to any one of a multitude of things. Our guide below outlines some of the more common fish illnesses and how to treat them.

Body Flukes

Body flukes are caused by poor conditions within a pond - things such as overstocking, poor water quality or species that are incompatible with each other. These types of flukes are often present in ponds, but if the conditions are correct there won’t be an outbreak.

Things to look out for -

  • Scratching against objects
  • Mucus covering the gills
  • Reddened areas on the skin
  • Eaten away gills

The best course of action is an anti-parasite treatment, something like the Interpet Anti Parasite Fish Treatments would be perfect.

Anchor Worm

Anchor Worms are introduced by already infected fish, therefore before buying fish from anywhere other than OATA approved Aquatic Centres, (although you could still do this just to be extra cautious), we would recommend you quarantine the fish for a couple of weeks if you have the facilities. This will allow you to see if they already have any diseases or ailments that may need treating before you introduce them to your pond with other fish and risk infecting them. These small crustaceans will burrow into the fish entering their muscles. Once they are buried, they will lay and release their eggs before dying, this can then cause infection.

Things to look out for -

  • Green strands coming from the fish
  • Red inflammation marks
  • Scratching against objects to try and remove the anchor worms

The removal of Anchor Worms is usually done by hand. After removal you would clean the wound with an iodine type rub. Some people will quarantine and bath fish in salt to help remove them as well.

Fish Ick

Fish ick is a very common problem in ponds, it is brought in from outside sources (birds, frogs etc) and it’s something you usually find in most ponds. Like other parasitic infections it will only raise its head if the water quality and the health of your fish is poor. This parasite requires a quick reproduction rate to survive so it must find a host within 48 hours otherwise it will die.

Things to look out for -

  • White sand like spots that are slightly raised
  • Clamped fins
  • Scratching against objects
  • Gasping at the waters surface

To treat this, use an Anti Parasite Treatment and quarantine any infected fish if possible. Then vacuum the pond floor if you have a Pond Vacuum.


Fungus in fish only develops due to a fish being in poor physical health, this will usually be after a parasitic outbreak, physical injury from a predator etc or a bacterial infection. This is probably the easiest of all to spot of the four ailments listed here.

Things to look out for -

  • Grey/white growth on the fish
  • Cotton wool like growth
  • Once the fungus sets in, if left untreated the fish will die

Use an Anti Fungus Treatment. Again, if it is not a water quality issue it’s always best to quarantine the affected fish too.