Cold salt water natives-problem!

[kdrun76]

I am a federal fisheries biologist. I have permits for all of my fish, no worries there. I don't get stumped often, but I am stumped now...


This is a tank in my private home, not a research tank. All fish in the tank have been in captivity for about 3 years. No new additions in more than 2 years. The fish have swithced tanks and been in different community configurations a few times but have been in the one they are in now for 10 months.

Its a 70 gallon tank, sandy substrate a few crabs, and a lot of tunicates.
I have 3 tuatogs (the largest is 4" long), 1 cunner (2.5") and a spot (3") that are perfectly healthy with no problems.

The problem is the mummichugs. I started out with 14 of them, they have spawned every spring (3 times now) that I have had them with the spot chasing down every last egg.

About a month ago one had a patch of white and nasty on his forehead. The caudal fin began to split and after about 18 days it died. bummer, oh well. 13 mummichugs. A second fish showed the symptoms followed by a third, only the progression was 5 days rather than 18. I have now lost 6 mummichugs in the last month. These guys are old. I know that. But there is something killing them. I don't know what the lifespan of a mummichug is, but I doubt its much more than a year.

I have just attained a bottle of penicilin to treat the tank with. I have also ordered an antibiotic food. I haven't treated a tank for illness in more than 20 years. My fish have ALWAYS been healthy. I am at a total loss for modern fish medicine. Anyone got any thoughts?

The patches on the forehead look bacterial, they eat through the skin and scales, expose the flesh, then the tail splits and the fish is dead with in 12 hours of the tail splitting. The only obvious wounds are on the head.\

Should I remove all the remaining mummichugs and treat just them, or should I treat them all?

 

[kdrun76]

I am really torn, Isolate the mummies and treat just them in a QT tank, or move the healthy fish to the QT tank and treat the main tank... or just treat everyone?

 

[gt1009]

I would treat the whole tank. Without a picture I can only speculate, but I'm guessing it is a funal infection, which can be treated by pimafix.

 

[kdrun76]

If I used a medicated food rather than putting antibiotics in my water, will that help?

I am concerned about putting penicillin in my water as I know it will kill the bacteria in my filter.

 

[Moontanman]

If it's fungus antibiotics will not help, I would suggest that 100% strength sea water 24/7 for a long period is having bad effects on a fish that is normally going to and from fresh to salt on a daily basis. i would suggest trying fresh water baths to see if they do better, you might consider they are old fish that would normally only live a year or so in the wild. Old fish have low immune systems just like old humans can.

 

[kdrun76]

I have had them on anitbiotic food now for about 60 hours with no additional losses and a substantial improvement in their appearance.

I did a water change on sat that took the salinity down to 24ppm. I will probably put it back up slowly starting next week as I don't think the drum will do well long term in water that dilute.

Nitrates are testing 10-15 ppm today, so they are staying low. Good sign.


I went through my records more carefully last night, first sign of a problem was noted 12/12/09 with the first loss of fish 1/9/10. Since then I lost 9 out of 14. Last fish lost was 2/3. My fingers are crossed.


Honestly when the first one got sick I was thinking exactly what you are saying, their old... its normal. But when they all started getting sick it was a major flag... quick order some antibiotic food or something!

 

[spotfin]

Just curious, what agency do you work for?

I would guess the mummichogs are reaching the end of their life span. You've done well to keep them for 3 + years. I catch all sizes up here in a large river. THe largest ones (up to 4" or so) are found in the salty end of the river.

Are any of the other fish (excluding the remaining mummichogs) exhibiting the fungus? I wouldn't treat the tank unless they do. Maybe increase the frequency of water changes.

If you can, remove the mummichogs to a qt tank and treat them there.

 

[kdrun76]

Only the mummies are sick. Every one else is fine. They were about 3" long when I caught them and were in water that was 29ppt. They have typically lived at 28ppt, until Saturday. So far the drum, cunner and tuatog show no indications that they have even noticed the sudden drop in salinity.

I work for the HMS division of NOAA and with the apex predators program.

 

[kzimmerman]

Spot of that size can do well in pretty fresh water. I've caught them in very low salinity near annapolis quite frequently. As far as the mummichogs go, around here I find them in full strength seawater quite frequently, in areas with no access to freshwater, so sustained salinity shouldn't be a problem. I would say that there was something in the tank all along, and the fishies just got old, and the immune system crapped out. To determine what it actually is, is the white stuff long and stringy or is it more fluffy? Is it thick or thin, and is it actually eating away at the flesh or is the flesh just dying? You can tell by looking at the wound, if it's red around the edge, its eating, if it's white, it's just dying.
I didn't know you were into natives, know you love gar, planning on a trip this summer on the pocomoke for juvie longnose if your interested.