Bog garden and pond advice please

We inherited two ponds. The smallest one is empty as it has a leak, and I was thinking of making it into a bog garden. I need some suggestions for small plants that will stay small, look pretty and the more unusual (and purple!) the better.
My other dilemma is the larger pond. It has fish in it at the moment, but the previous tenant is coming to get them anytime, and I don't want to put more fish in it once they've gone. It needs a good clean out and then I'd like to put a nice water lily in it and keep it more as a wildlife pond. It has a few things planted in and around it but I'm not sure what's alive or dead at the moment and it's really clogged up with some kind of pond weed and stems of something. Any advice gratefully received.

 

The stuff that looks dead in the bigger pond will start growing again soon. You can always cut the dead foliage away. It's hard to get rid of pond weed without a total clean out of the pond. Maybe leave the pondweed there and just stick your water lily into the middle.

Don't know about small purple marginal plants for your bog garden. Maybe? Astilbe? Lobelia Queen Victoria? Purple Loosestrife (But that's tallish) Ligularia (the purple-leaved one)

 

Water Iris come in purple shades

 

@SparklyPurple - wildlife ponds are a great habitat for wildlife such as frogs, newts, toads and a whole range of insect larvae if the pond is of sufficient size and area.

However, one thing is guaranteed and this is mosquito larvae, which can prove a serious nuisance on your doorstep if they are kept unchecked. A relative made a small wildlife pond in her rear garden and it was impossible to enjoy a summer evening outside without being practically eaten alive by mozzies. Once the pond was filled in, the problem ceased.

Just saying that if you enjoy your summer evenings al fresco without wearing overalls, you need to get the pond to a sufficient size to encourage Drangonfly larvae, or oxygenated enough to keep 'wild' and hardy fish such as Rudd and Roaches that will eat the larvae

 

Watermint has lilac flowers and releases a wonderful fragrance when brushed.

I had a raised container pond a few years back and two goldfish. I did not get any mosquito larvae, so assume the fish ate them. I did get them in the water butt though.