Having a pond or water feature in your garden has many benefits. Apart from the aesthetic pleasures, ponds can be cooling, and provide an opportunity for increased biodiversity in your garden.
In Perth, we have many species of frogs. Providing a safe place for them in your garden is vital as the population continues to encroach on their original habitat.
Frogs are particularly sensitive to chemicals and their presence generally indicates a healthy environment. They will do their part in reducing insect pests.
When designing your pond, it is useful to have a small 'bog garden' as part of the plan. Many of our frog species actually need this permanently damp soil to breed successfully. Also think of including plants in and around the pond to provide safe havens and a method of frogs exiting the water. (See our links and resources page for more details on frogs & frog pond design in WA!)
Having fish in your pond will prevent mosquitos breeding, but we recommend you carefully think about your choice of fish. Goldfish, Koi and Gambesi are all non-native fish that compete with native species and will eat frog eggs and tadpoles.
When choosing fish for your pond, selecting native species (that have evolved with frogs) helps ensure our amphibous friends can continue to breed.
We stock two types of small native fish which are found naturally around the Perth metropolitan region (or at least used to be!) and throughout the South West of WA. These fish are obtained through licensed breeders.
We do not recommend you 'catch your own' from waterways. Besides being illegal, small fish often thought to be native are usually the agressive Gambesi (eg. in Lake Lechenaultia). These fish were deliberately released into creeks, rivers, etc. all through WA eighty odd years ago - supposedly to reduce mosquitos. However they have since been found to be less effective in mosquito control that the native varieties - but unfortunately tend to out breed and out compete the natives.
The varieties of Native Fish at The Green Life Soil Co. are:
Western Pigmy Perch: Edelia vittata
Occurs naturally in the Perth Metropolitan region and South West W.A. It is a small fish which is variable in size from 5cm to 15cm approx., given the size of the pond and available food.
Normally olive green/tawny brown with golden stripes or patches, during the breeding season in spring the mature males have black, orange and golden colours. In the wild this species typically lives for one or two years, but in captivity can survive much longer (around 6 years has been recorded).
Pygmy Perch are excellent aids in controlling mosquitoes and midges, but do not interfere with frogs which may be also breeding in your pond. The fish need plants to provide cover for protection from predators, and to provide food.
Providing your pond has adequate plant life, additional feeding of your fish shouldn't be required, although regular 'goldfish' food can be given to pygmy perch if necessary. Naturally timid, they are good at hiding from predators and as such, once introduced to your pond may not be seen again! Possibly more visible in the evening if you 'train' the fish to come to food and are prepared to be patient.
Western Minnow: Galaxias occidentalis
Also occurs naturally in the Perth Metropolitan region and South West W.A.
Not as much is known about this fish, although it is much larger then the Pigmy Perch.
Also excellent at controlling mosquitoes, and capable of preying on much larger insects which it will snatch from the surface of the water. Western Minnows have similar needs to the Pigmy Perch, needing plants for cover and to lay eggs in.
They are much more animated, patrolling their environment in schools at high speed, and have a habit of launching themselves at fountains or waterfalls, presumably to swim upstream. They will also leap out of a pond when first introduced if the pond walls are vertical so it would pay to cover the pond for a day until settled. Western Minnow: Galaxias occidentalis. Also occurs naturally in the Perth Metropolitan region and South West W.A.
Introducing fish to your pond
Float bag on water and leave a while for fish to acclimatise to temperature. Introduce a portion of pond water into the bag (about a litre at a time), this also allows the fish to adjust to any difference in pH. The longer the period of time you do this over, the less chance of stressing the fish.
Five or six fish will give you a good breeding group. It is thought having at least two males will prove more successful in breeding.