From Raccoons:

• Don’t waste your time with repellents, lights, sounds (audible or not), or odors.
• Use native fish whenever possible as they are harder for raccoons to see.
• Grow sedum or other spongy type plants around as much of the pond as possible. This plant makes it difficult for the raccoon to feel it has a secure place to stand on and can disrupt its balance as it reaches to scoop fish.
• Install deeper ponds to provide more security as they are less likely for a raccoon to wade in. However, the surface of the pond needs to be balanced with depth so that the fish obtain sufficient oxygen, especially during the winter in northern states.
• Provide underwater structure so that the fish have more places to hide if the raccoon misses on the first pass.

From Bird Predation:

Step 1. Know the law. All migratory birds are protected, even those attacking your fish. They cannot be shot, trapped, or otherwise harmed, without a permit from the U.S. Fish and Wildlife Service and your state’s division of wildlife. This includes their nests.

Step 2. Consider the legal options.

• Exclusion
  • Completely enclose small ponds, tanks, and/or raceways with screen or netting.
• Impediments
  • Partially covered systems with overhead wire, line, screen, or netting. Perimeter fencing or wires.
  • Metal spines, cones, or electrified wires for roosting problems.
• Cultural Methods
  • Consideration of local bird populations, construction of pond margins and bottom profile, location of fingerling ponds, and feeding techniques may lessen damage.
• Frightening
  • Various devices available include reflecting tapes, eyespot balloons, scarecrows, automatic exploders, pop-up scarecrows with exploders, pyrotechnics, alarm or distress calls, lights, water spray devices.
  • Aerial harassment with ultralight aircraft, radio-controlled model airplanes; ground harassment with vehicle patrols.
  • Roost dispersal may move depredating birds from the area.
  • Avitrol® is a chemical frightening agent for herring gulls and blackbirds.
• Toxicants
  • None are approved for use by federal or state agencies.
• Trapping
  • Except for some blackbirds, trapping is not allowed without a permit from the US Fish and Wildlife Service and upon recommendation by the USDA-APHIS-Wildlife Services. Permits are issued to complement ongoing nonlethal methods. Check county or state permit requirements.
• Shooting
  • Same as for trapping, except that some blackbirds may be shot. Ducks may be hunted during waterfowl hunting seasons.