Epoxy pond liners were around when I started building ponds back in 1987. There was not a market for the epoxy for the residential contractor or do-it-yourselfer yet because there was not much of a pond market yet. The epoxies made then were for large commercial applications where waterproofing was necessary and huge machines were available for mixing and spreading. We tried to mix it using a paint stirrer on the end of a drill, but the results were disastrous and getting the epoxy off whatever it got on was almost impossible.
In recent years the makers of epoxy pond liners have made great strides in research, development and application. Building a pond using epoxy can be done by the small contractor or the homeowner. It is easily mixed and applied. But do be careful. Getting on your hands or clothes means living with it the rest of your natural life.
One of the most wonderful uses for the new epoxies is for patching concrete ponds. I have told my concrete pond owners when they called with a cracked, leaking pond that there was nothing that could be done. I would put some plumbers' epoxy in the crack and tell them just to keep on doing that every time the pond cracked again. And concrete cracks in tropical climates where most of the land is below sea level. Now a crack can be patched just like patching drywall. Use some cloth made just for epoxy use, insert it in and over the concrete crack, then float the epoxy over it. Most installers proceed to coat the entire concrete pond because it looks better and will stop further (and inevitable) cracks.
PVC liners came first in the pond-building business. They were all we had, so we loved them. Their biggest drawback was not standing up to sunlight. PVC liners cracked like visqueen and needed replacement if the pond wasn't built so that water covered every bit of the PVC liner.
Rubber liners were next and will undoubtedly rule the industry for years to come. If you want to know what a rubber liner is, just think about a huge piece of inner-tube material. That's a rubber liner. Firestone makes them. I am sure many other companies do as well. A 45 mil thick liner comes with a 40-year warranty. They run about $1.00 a square foot, although you can get them online for less. The biggest drawback of online buying is paying the shipping, but often you can still save money. The next biggest drawback with rubber liners is weight. If you buy a 45 mil rubber liner that is 20' x 20', you better have a couple of strong guys to put it in place for you. I still love rubber liners and since they have become widely available, I have used them exclusively. Rubber liners withstood anything Katrina threw at them. My customers and I were happy to see them whole after seeing everything else destroyed.
I think epoxy is coming into its own. It may well be that it will be the liner of choice one day. As far as I am concerned, the ability to patch a concrete pond is reason enough to love it.
Mosquito fish are a great natural solution to the problem of landscape pond insects, but you'll need to take some steps to keep your fish healthy.
Pond leaks are not fun. Noticing a water level drop, you are sure you face repairing your pond liner. Before you panic, make absolutely sure it is a leaking liner and not another problem.