in the bass pond. They are blind in both eyes and are dark in coloration. One odd thing that happens to fish once they go completely blind is it effects their pigmentation. They turn pitch black.

I've easily netted and removed two from the pond. I'm almost positive it's due to eye flukes that are part of a snail/heron cycle. It starts out with popeye or exophthalmia and then the fish go blind. They also become emaciated due to not being able to feed.

Anyone else observe this? Fortuantely it's only a small part of my population but it sure makes one want to blow those damn birds away!

Dang, Cecil, just another problem to worry about!

Wonder if there's some kind of critter that feeds on the parasites before they infect the fish?

The wildlife guy told my neighbor that stocking redear sunfish is almost a must down here. He says they are needed to control some kind of parasite. Redworm, I think. There should be *something to interrupt the cycle of the flukes.

Cecil, we had one LMB and one bluegill totally black. The bluegill lived one summer but the LMB lived two. Yes, they were blind. We have a LMB now that is blind in one eye (from hooks I think) but it can find pellets easy enough so has no problem with feeding.

Cecil, I've considered the grim possibility that all of the work we've done to try to keep YOY (young of the year) fish out of our ponds could be contributing to certain type of parasitic infections. I do know that anchor worms, which can cause blindness if they attach near the eye, have a free swimming larval stage which MAY possibily need many YOY fish to keep it in check. I hope that's not a mitigating factor for you.

What would you attribute the color change to? I've caught starving bass that were of normal color so I don't really understand the black color.

I've been assuming it was because the fish no longer had visual cues to use in setting it's chromatophores (sp?). Anyone have the real answer?

Theo's right.

Fascinating! That may say a lot about the lack of pigmentation in cave fish. I thought it was the lack of light.

It may say a lot about the pale color of the bass I used to catch in a lake with a lot of suspended sand. They didn't even have a colored lateral line. The lake was so muddy and the water so sand colored that you couldn't see the bass in a livewell.

Lack of light causing darkly set chromatophores
has the problem of contradicting what we normally
see. That is the more opaque the water, the lighter the fish is. If there is no light there is no need for camouflage, hence pale blind cave fish.

Many cave fish have nonoperative eyes { that is they don't work on visable light} . Over time with no light there is no use for eyes so the fish evolve to the point where they do not work. No eyes , no light, no need for color none of that is needed.

My guess on the bass or BG , which do operate in a light envior. and need operative eyes is that the chromatophores are keyed to colors/light viewed by the eyes .
White is the lack of color , black is a mix of all colors. If a fish is surrounded by lack of color {white sandy bottom and/or in opaque water} it is light colored. If it is surrounded by dark {no light or dark bottom or water } it is dark . If the fish is blind and detects no light or colors it turns dark.

When I kept BG and bass in my aquarium at night I would turn off the light wait about 30 seconds and turn it back on . In the process the fish coloration would go from light to dark and back to light . If I changed the background they would change to reflect the background color .The same with the rocks/sand in the bottom. The BG would also turn dark { I think as a warning} when they were aggravated . I have also read that bass eyes may be able detect light that we can't see like infrared or UV which are above and below our visual light spectrum . I don't know but that would be interesting . ewest

Theo and Ewest.

Very interesting!

Bruce, the bass are in a pond that is not my primary bluegill pond so I am optimistic with the bluegill. Additionally I've had blind yellow perch and bass but no blind bluegill. Not sure if that means anything.

Hey guys bluegills in the bluegill pond are going crazy under the Will 'O ' Wisp buglight! They absolutely love to suck in bugs under the light. They are presently sucking in small white bugs and seem to have limitless room in their stomaches for the things. Sure hope it really makes 'em grow!