Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Diseased shiners?

I put leftover shiners from icefishing in my two year old trout pond. Quarter acre, 9 ft deep, aerated. The population has exploded. They are obviously reproducing well. I don't know specifically what species of "shiner" they are. My understanding is the quality control on the shiner bait industry is not ISO grade.

About two weeks ago I started noticing discoloration in the normally dark backs of the shiners. Close examination shows whitish lesions. Some are dying, with about 50 or so dead on the edge of the pond surface - at least to my casual observation.

However, there still seems to be lots of shiner activity at the surface. And the "big" shiners of about 4-6" are not dead. No trout have died. Just a bunch of the smaller, as described.

Qs:

1) Any diagnosis or explanation out there?
2) As long as mortality doesn't hit the trout population, should I be concerned? Is there usually disease crossover from species to species?
3) The trout seem to be actively feeding - I see them hitting the surface. And even though they are pellet fed, they are not hitting the pellets hard - they seem to be going after live forage. I assume that includes the shiners. Is that a bad thing?
4) A guy up here in the region says I should buy a block of salt used for livestock. Split into four chunks and place it in various parts of the pond. Says it is good for skin infections on fish. Do the Pondboss guys buy that?

1) I'm far from an expert, but it sounds most like a parasite or fungal type problem to me (I know that's not really nailing it down, Sunil).

2) Some diseases cross species lines, but many are family or even species specific. If I were you I wouldn't panic as long as the trout remain healthy. If they are eating well and active, they are probably not stressed - stressed fish get sick much easier than healthy fish.

3) Does their condition seem good? If they have plenty of natural food, limited interest in pellets is understandable and not, I believe, a cause for concern.

4) IIRC Bill Cody recommends a salt water dip for fish being introduced into a pond from the wild; I don't know if slightly brackish water would be useful for the problem the shiners have.

Hey Bill Cody, you out there?

"I know that's not really nailing it down, Sunil"

Please try harder, Grasshopper.

When you can snatch the pebble from my hand....

Thanks Theo. It sounds like I should be patient. The trout seem actively hitting the surface for natural forage as well as pellet feed.

You've not heard of adding the salt blocks to the pond? It was a local hatchery/fish producer that recommended it - without knowing anything about the shiner's condition.

Again, thanks for your help.

There's some merit to putting salt in the water. I don't know the details, but I know my fish guy uses salt from time to time and it perks the fish up.

It is also used in live wells for C&R fishing; IIRC it relieves stress on the fish caused by osmotic differential (I think in the gills) in addition to perhaps having other benefits. Did Bruce once post he thought his fish had some health advantage due to his ponds' higher salinity content?

Sunil, Theo, sounds good. I think I'll buy a block and put it in as instructed.

I'll let you guys know if I see any measurable difference in the health of the shiners or of trout.

Have you guys ever experienced a die-off of minnows or forage - like my pond is experiencing to some degree - where the predator species remains okay? The white fungal patches on the minnows is fairly prevalent.