Nepen; I feel your pain. I've recently been battling with the deer the past few years, ever since a new housing development eliminated a nearby forest and pushed all those inhabitants into the neighborhood proper. I have lots of hostas and apparently, it's also like candy for deer. I thought to try the Deer Off, and their like, but the cost is probhibitive (to me) because I have so much area to protect (not my pond, but my gardens).
So, after doing some research, I now spray this concoction, as it's easy enough to make, and inexpensive; 3 eggs, 3 cloves of garlic, tablespoon of cayenne pepper, 6 oz. of red hot chili sauce and a quart of water. All go into the blender. Then I add another 4 gallons of water, filter out the large particles, then let it sit in the sun (covered) so it ferments. I then put it in a sprayer and spray whatever I think the varmints will eat (I'm also in a death struggle with the woodchucks and this stuff supposedly stops both). This solution gets stinkier by the week, but I figure it's worth it if the deer and woodchucks stay away. Only had one slip this year and a couple of hostas got it, along with not seeing the day lily buds soon enough!
This is the trick though, as already mentioned; you have to keep your stock sprayed. And since it HAS been raining a lot, I do it every day after a rain and when not raining, once a week. The idea is that the varmints won't take more than a bite and then a pattern is set so they leave your stock alone. I have had to upgrade my diligence though because last year, I started out fine, got lazy, had a large chunk of hostas served as lunch for the deer, and found I knew many more curse words than I ever thought. So, this year, I'm being religious about this, hoping to break any patterns and actually be able to see what some of my day lilies look like!
I don't thinks this recipe will adversely affect your pond as it's all natural and most of your spraying will be on the foliage. I don't 'wet' the leaves; I just spray lightly as you're only trying to alert the deer to the smell and probable bad taste.
I also did the 'green string line' trick, and it does seem to help. The idea here is that the deer can't see well, they bump into the string, get confused, and go around/back away. I have one line strung along the perimeter of my yard at about 5' and one at 3' (for the lil deer munchers). Since it's green, it's really hard for me to see it. If you have kids running through though, might want to put some tin foil/dangly silver for both deer and kids.
Anyway, just some ideas. I never thought I'd ever see a deer in my neighborhood and now, I wish I didn't! And, a couple of years ago, we had a coyote go running past as we sat in the pondhouse! And I live in a suburb! Btw, I DID try the coyote urine too but found it wasn't that effective and cost a lot more than my concoction.
Hope you can get a handle on your dear deer problem!
Michael
I saw some flowering bulbs though 
