BULGING eyes on bluegill?

at school, there is a small pond that we catch bluegills from with dipnets and keep a few in aquariums in class.

well today we found a minnow trap in the water and it had obviously been there for a long time, because it was totally covered in algae and scum, and there was a bluegill inside who was about 4" long and too big to fit through the holes, so the only logical answer is he got trapped and grew too big inside the trap.

this fish had huge bulging eyes. it was also very skinny. guess there aren't many opportunities for food when you're stuck inside a minnow trap.

there is also a smaller bleugill in the aquarium that we caught a while ago that has bulging eyes too.

what causes this?

Edited by dsaavedra, 10 February 2009 - 06:55 PM.

IME, most bluegill that have extremely bulgy eyes have a parasitic worm inside the eye. Here is a picture of a "fresh" one, taken out hardly 5 minutes ago, with the picture being taken almost immediately after it being pulled out of the eye. Apparently the parasites cannot survive long without a host, because between the time I took it out and took the picture, the worm was dead and emaciated. It was about 3 times as thick as it is in the picture (I'm guessing full of blood) and when I took it out and put it in water to take a pic its bodily fluids started oozing out of it and within a minute or so it was dead and shriveled down to almost nothing. It's about 2.5-3 cm in length, and that's pretty big for a small bluegill's eye (hence the bulging).

hmm that is interesting.

if a fish is infected with this, can it spread to other fish in the tank?

hmm that is interesting.

if a fish is infected with this, can it spread to other fish in the tank?

I'm not sure about that one. I'm sure Centrarchid knows. Maybe he'll chime in in a bit.

I am not a parasitologist or fish health specialist so take what I write with a rain of salt.

Based on what I have read, the parasites involve can infect tankmates of the initial host. I have not seen such horizontal tranmission in my aquariums with the fishes and nematodes they occasionally carry.

I am not a parasitologist or fish health specialist so take what I write with a rain of salt.

Well, I mainly based my assumption mainly on the fact that you work with sunfish, and that you had probably seen this before, since it seems to be a pretty common bluegill parasite.

Edited by fishlvr, 16 February 2009 - 09:24 PM.

This is more a general question to all who have access to journals and so forth, but is there much work being done on parasites in our native fish? I need to purchase the "Parasites of North American Freshwater Fishes" book by Hoffman. It is a field I could easily see myself getting into.

Blake

This is more a general question to all who have access to journals and so forth, but is there much work being done on parasites in our native fish? I need to purchase the "Parasites of North American Freshwater Fishes" book by Hoffman. It is a field I could easily see myself getting into.

Blake

The study of parasites like those found in fishes seems difficult to fund, therefore little work is ongoing relative to other aspects of fish biology. Maybe this is an area worthy of its own section within the this web site. I can recall this nematode topic coming up several times.

The study of parasites like those found in fishes seems difficult to fund, therefore little work is ongoing relative to other aspects of fish biology. Maybe this is an area worthy of its own section within the this web site. I can recall this nematode topic coming up several times.

Not to sound like a know it all but the bulging eyes is know as exophthalmos among fish pathologists and can also be due to a number of bacterial and viral diseases. Is it possible the emaciated fish succumbed to either of these two due to its weakened condition?

I have seen exophthalmia in cultured fishes likely associated with microscopic pathogens. The same gross clinical signs (eyes bugging out) associated with wild fishes are just as likely to be associated with the presence of nematodes behind the eyes which can often be seen through the membrane surrounding eyes. I seldom see the nematodes among cultured fishes unless considerable interaction with natural food chains has ocurred.

I have seen exophthalmia in cultured fishes likely associated with microscopic pathogens. The same gross clinical signs (eyes bugging out) associated with wild fishes are just as likely to be associated with the presence of nematodes behind the eyes which can often be seen through the membrane surrounding eyes. I seldom see the nematodes among cultured fishes unless considerable interaction with natural food chains has ocurred.

Make sense to me. What about fish that seem otherwise healthy but seem to have eyes that stick out more than normal? Is it possible it's just an individual difference and not related to any specific cause? Both eyes on this close to 3 lb. yellow perch were out farther than I normally see. She wasn't caught in deep water either.

Make sense to me. What about fish that seem otherwise healthy but seem to have eyes that stick out more than normal? Is it possible it's just an individual difference and not related to any specific cause? Both eyes on this close to 3 lb. yellow perch were out farther than I normally see. She wasn't caught in deep water either.

Some of our monster, apparently sexually senile bluegill, exhibit the bug eyed look. The same animals also tend to be fat with fluid buildup in abdomen like with dropsy.

i've always wondered, how come the eyes on huge largemouth bass (10lbs plus) are always very buggy?

i've always wondered, how come the eyes on huge largemouth bass (10lbs plus) are always very buggy?

Yeah I've seen that in pictures of really big ones in fish tanks as in Bass Pro Shops. So maybe there is a correlation between large obese fish and buggy eyes? Maybe "fatty livers" have a correlation too?