I've stocked different species in my pond over the years and I'm curious what land animals may invade the pond and eat my fish. Cormorants tried once but my dogs chased them off and haven't been seen since. No sign of beavers or otters. What else could reduce fish populations?

There might not be enough baitfish in the pond to the point the fish are starving, or maybe people are taking the fish that you have stocked.

Snakes eat a lot of fish here. Northern diamondback water snakes, plain bellied, broad banded, several types around. Snapping turtles are predators and are found as far north as Canada. Spiny soft shelled turtles are also predators and range into New York. Grebes, loons, anhinga, kingfishers, all eat fish. Believe it or not, Barred owls feed on fish occasionally.

If there is a lack of cover, some dominant fish might be eating a lot of the competition. The lake I live on has not the cover amount that’s ideal (many fish artificial cover structures have now been added) and fish like bluegill get decimated by predators like largemouth bass. A sign of insufficient forage is skinny predator fish. Insufficient forage is often a result of lack of hiding places for them to escape the predators.

So many potential explanations for low fish abundance. Anything from poor bottom substrate reducing spawning success to lack of suitable nursery habitat to poaching. Can you give us a fairly detailed summary of your pond including details like age, water chemistry test results, the number, date and species of all fish stocked, history of fish kills (you mentioned ice-over oxygen kill in the other post), any habitat installations, herbicide treatments, water chemistry treatments, nearby land uses, etc. The more detail the better for ironing out the most likely culprit(s).

Cormorants aka water turkeys of course are numero uno....and they are sneaky. I wouldn't worry about snakes or turtles unless they are overpopulating. Other bird predators include the herons and around here Eagles.

The most devastating, however, predators are the otters. They will completely clean out your pond (s). If you have a near-by creek, even if it is only wet weather creek, they will move along that creek and find your pond(s). Once they strip all the fish, they move on but will return periodically to check things out. Very destructive to fish ponds. Control is extremely difficult...they are mostly nocturnal. Very hard to detect...but if you have a near-by creek, I can almost guarantee you have been visited by these indiscriminate fish killers.

Another critter which I've found to be predatory on pond fish is the nutria. The "books" say they are vegetarians but not so in my experience. They need to be removed from any pond not only for predation, but for tunnel building which can undermine your pond dam.

A lake resident of the lake I live on likes to catch crappie for the table. He puts the live crappie he catches in a largish live trap that is out on the lake at the edge and then scoops them out when he’s ready to clean them. He goes to clean his fish and notices several of the crappie are missing. He checks his trap and that looks good and fully intact. But, then it happens again. Is someone stealing his fish? He sets up a camera covering the area of the trap. Who do you think was taking the crappie? Otters, that’s who. The otters were able to lift the lid to the trap and pilfer the live crappie. Smart water weasels, they are.

I have never seen one on the lake and I look at the lake all of the time. The only other evidence of otters is the one I saw dead on the road, hit by a car, 20 feet from the lake the only place the road skirts by that close. There’s a ditch there that feeds into a creek about 200 yards from the lake. We used to have a lot of nutria and they are destructive. Somehow by unknown means, those alien rodents are all gone and not missed.

Cormorants and ottters are the biggest offenders. I did not see a mention of pond size, but a large flock of cormorants could create severe shortage of fish in just a day or two on a small pond.

On another note, I sat in a lake mangagment seminar a few years back and a lake management owner, with more than 30 years experience, was asked "how much damage can an otter do?" The reply was "one otter is likely the equivalant of 50 cormorants." Folks, if you have otters, and they stay for very long, you will have a depleted source.

IMO, snakes and turtles are more scavengers than predators and would likely not have a significant impact.

Raccoons may be part of the problem.

Blue Herrons around here are a problem

I have seen snakes underwater hunting small bass. Not saying they do it often or with great success but they sure were going after those bass fingerlings.

Otters, as mentioned, should be investigated.

What about a virus?

All pond owners should shoot every Cormorant they can, never let one live.

Actually, in my experience, shooting at them is very effective...a dead water turkey isn't nearly as effective a deterrent as a water turkey w/red [censored]. They communicate well with others.

My rule: Never, ever allow water turkey (s) to eat, sun, poop at your pond unmolested. One brings buddies, and buddies bring more buddies. You can't kill them all...and in fact effective control can be established without killing.

Coons and Big Foot

are turtles any help at all in a small pond. Mime has a lot of them.

they sharpen my shooting skills....