Poor water quality...can be linked to one or several causes...

1. Lack of oxygen especially in green water. Add oxygen with plants or fountains or waterfalls.

2. Overstocking. Only allow 2" of fish per sqft of surface area.

3. Over feeding the fish, especially in winter. Dont feed below 10c.

4. Decaying fish food or a build up of decaying plant matter. Net off all excess food at feeding times and only feed what they can eat in 5 or 10 minutes.

5. STRESS for any of the reasons above or below. Stress increases a fishs metabolism, which in turn pollutes his environment further inducing more stress.

6.POLLUTION. This can come in a variety of forms:

(a) Fertilisers and weed killers leaching in or drifting in from spray. Glysophate weed killers are harmless to the pond inhabitants, but spray drift can kill the plants. All other weed killers are harmful to plants and fish.

(b) Lime or cement chemicals leaching in from fresh ornaments, from stone edging or from under newly laid paving edging.

(c) Chemical treatments and preservatives and solvents used on woodwork for jetties or decking.

(d) Metal poisoning from copper fittings used in the plumbing of pumps etc. or galvanised mesh, or money.

(e) Trees and other plant life in the vicinity like oak, elder, laburnum, yew and willow.

(f) Bonfires, traffic, overhead aircraft.

Bonfires can have a potentially deadly polluting effect on ponds.

(g) Uneaten fish food and particularly inappropriate food given as food for fish.

This poor pond in this pretend village green at the Cheddar Cheese Factory visitor centre never had a chance. Apart from the staff continually feeding the fish with bits and pieces from their lunches and cheese allowance, the tourists would emerge from the caf to the right and unload their leftovers into the pond. The fish were permanently sick with fungal disease as result with regular casualties to this kindness.

As any of these factors cause stress to the fish, so their metabolism increases and they produce excess ammonia from their gills. In a confined environment the ammonia is highly toxic and in its turn causes the fish even more stress. A downward spiral therefore quickly develops in a small pool. This is repeated several times in this book if only to emphasise the importance of the quality of the environment (i.e. water) on the health of the fish.

Prevention is better than cure and get started on the right footing (see "Avoiding Problems From the Start").

(g) The filter itself can be the polluting agent. If a toxin-producing colony of bacteria has become established in the filter through irregular use or lack of management then this can cause stress that does not register on any water testing equipment. If this is suspected after a water test, clean the filter out and start again with fresh medium.