Ponds, Ducks and Other Wildlife

We have a pond about 20m (60ft) square and 1.5m deep in winter.  It is home to some small black-looking fish and lots of toads, dragonflies etc. It has water lillies in it that are really quite overgrown and congested but it also has that horrible pond plant in it, parrot feather (Myriophyllum aquaticum) that has taken over the place.  Now, in this extra hot and dry summer the pond level has fallen to about 15cm (6in) and only in the middle.  The parrot feather is so thick that the fish can no longer swim in it and are dying so today I have taken the decision to put some water into the pond via the mains water hose.  I was trying to avoid this as it seems a 'waste' of water but there's no rain forecast and I can't just stand by and watch all the fish die.

So questions...
1. Is it possible to keep a pond's level up somehow - and down somehow?  I ask this because I also have some plants to go in that like their feet in damp soil.  Near this pond they'd be high and dry in the summer but swamped in the winter.

2. Would ducks eat the parrot's feather?  Would they also eat the lillies?  Would they also eat the toadspawn?  I really want to be rid of some of this disgusting weed that's choking everything and making the pond into a horrible brown mess.  But I still want to have the toads as they are my slug-busters.

I think to get rid of your parrot weed you will need gum boots, rake, compost heap and hard labour 

found this may be of interest

www.weeds.asn.au/weeds/txts/parrots_feather.htm

just disreguard the mention of chemical use

a good thing to do would be to get pigs and corn and a shovel and a fence

dig the areas that need to get deeper and have the pigs root out the corn and make a wallow and seal the pond

groundwater ponds of that depth with no freshwater inlet will go dry in summer droughts..or nearly..and your fish will die off..period.

if you can afford to add the water..and want to do so..then do so..but do remember it will evaporate and you'll have to continue to add more to keep the water level up.

the best way to solve the problem is to deepen the pond..

we started out with a very shallow pond ..it would dry off in summer drought..my son deepened one area to 5'..or so..and it has never gone dry..last year we deepened another very large area we added on to the pond..and that also remained wet enough for the wildlife to thrive in it..

the shallow areas still did go dry..but with the deep areas holding water the wildlife was able to go to the deep areas to live.

we would have liked to deepen the entire pond..but we just didn't have the time when we had the equipment..only had 1 1 /2 hours..with a backhoe.

but are so glad we were able to deepen what we did.

one day we do hope to have a freshwater inlet with a flowing well..when we can afford to have it put in