I have been keeping Riv. simplicis since 2005. For the first 2 years, I had no problems with them at all. I produced and distributed dozens of fish. However, in 2007 I noticed that my adults (even young adults) could not swallow food. They attempted to eat, seemed to be "chewing" the food and then spit it out. This was true of any live or dried food I tried. I tried adding flubendazole to the tank, but it didn't help at all. Eventually, an entire 10 gallon tank of fish just starved to death. Then, in 2008 I received eggs from a friend and raised them to adulthood. The same thing is now happening to most, but not all, of those adults- they cannot seem to swallow food. Again I tried flubendazole and again it wasn't any help.
Anybody have any ideas for me to try?

Dan Katz

Hello Dan & Sue,

It seems to me that some other factors are playing a role in the fact that they are not eating well.
However, i think we need to know more information as to general fishkeeping, to asses the problem at hand.
For instance, what is the PH and the KH + GH?
Have you checked for NH4 and NO2 ? is your filter working?
Have the fish been raised in the same tank, or being moved?
Are you feeding them daily, twice or more?
What are you feeding them? Live, frozen or dried?
Have you changed water source? What is the temperature?

First i would try to get the best optimal water conditions, and i would also add salt.
Flubendazole is used to treat internal worm infections, while it does have a little anti-bacterial effect, you probably need a good anti-bacterial medication such as Metrodanizole:
If the fish are not eating fresh artemia, then i would definately use the Metrodanizole. This is some type of antibiotic (i think) therefore it is important to use it at least 3-5 days and not skip a day.

If all fails, after a certain amount of time (fish need time to heal and adapt to good conditions), you probably would need to contact a good veterinary specialised in fish. Perhaps Barry Cooper can assist? :)

Good luck and hope all goes well.
Tom

When killies can't take food, it suggests that their throats are swollen. This can be caused by an over abundance of flagellates, usually held at bay by the immune system. Somehow the Rivulus might have been stressed. (Let's save time and not mention the many ways I've stressed killies).

Do the usual stuff we do to make the tank even more comfortable for them. The wee beasties are sometimes referred to as Hexamita or Spironucleus. Metronodazol is often recommended for treatment. One may have to cruise labels in a pet shop, but it should be available, despite what last Monday's hire says.

It is funny how certain anthelmintics can effectively treat some wee beasties and not others. I'd have tried what you did first too.

A little bit more is at
http://www.aka.org/aka/modules/newbb/ ... ost_id=3453#forumpost3453

Mostly that is based upon what others have told me.

Good luck and all the best!

Thanks to both of you- Tom and Scott- for your thoughtful answers. I plan to buy some Metronodazol tomorrow and I'll let you know how it works for my Rivulus simplicis.
As far as answering all of Tom's questions, here's what I can tell you:
First, I can kick myself in the ass for not measuring any of the water parameters in the stinky, polluted swamp water in which we collected the wild pair. Nevertheless, the wild pair was initially kept in rainwater at my room temperature. That water temperature (in my basement) varies seasonally from about 68°F up to about 77°F. The wild fish and the first couple of generations from them spawned at temperatures above about 71 or 72 °F. They ate just about anything including live baby brine shrimp, daphnia, Grindal worms, flake food, dried krill and freeze dried blood worms. Some of the young were subsequently raised in my well water, which contains from about 500 up to about 1100 PPM of TDS. The dissolved solids are mostly salt, NaCl. All of my tanks are filtered using sponge filters and all get about a 1/4 to 1/3 water change weekly. My well water comes out of the tap at pH 6.4. I never measured the pH of my rainwater, but it's probably pretty acid. The fish that have been starving themselves to death have been in tanks with both rainwater and well water. The starving has occured at both extremes of water temperature in my fishroom.

Well, it's been 16 days since I started to add Metronidazole every 3 days to the tank with the starving Rivulus simplicis. It looks like a success at this point. It took over 1 week, but all but one of my fish seem to be eating again. They're eating mostly tiny foods like newly hatched brine shrimp and Grindal worms. Some attempt to eat larger particles like pieces of dried krill but they still can't swallow the larger foods. So, my plan is to keep adding the Metronidazole every 3 days for another couple of weeks and then I'll decide how to proceed from there.
Thanks again for the help.
Dan

Hi Dan,
What has happened to the fish you have distributed? Have they met the same fate?
Regards,
Sandy

That's an interesting question Sandy. Unfortunately, I don't keep details of fish or eggs distributed. And, my memory is near useless. Here are 2 different results, though:
I sent one pair of fish to Ken Normandin in Florida a few years ago and his fish starved to death.
Prior to that, I gave either fish or eggs( I'm not sure which) to Joe Komarak in New Jersey and his are still doing well after about 3 years. In fact, he gave me eggs 2 years ago to get me started with simplicis again.
Did I ever give you this species ?
Regards,
Dan

Dan If there is swelling in the throat area of your Rivs add a couple of drops of Marine Iodine per Gal! In a few days, 2 or 3 They should be eating well. Regards Nick V.

Dan I really feel that your Riv's a have case of Goiter, Try the Iodine on a few fish. I have had the same situation with my Diaptrons, Annulatus and some Ep. after a couple of generations. I now buy Marine Iodine and ad it to my water tubs as per directions on label , since starting this regiment of care I have not had a single case of Goiter.If your fish are still unable to swallow foods larger the Brine Shrimp after the treatments that you have tried,Please try the Iodine................Regards Nick V.

Thank you Nick!

We chatted about this on the phone. I will admit to never even thinking of the possibility of goiter. I would still check for "Hexamita" first, but that could be a very significant place to look if the first hypothesis doesn't work.

One can read of goiter in several pieces of aquarium literature. The only place I ever have seen it was in a pupfish tank at Al Anderson's when Kurt Bihlmayer and I dropped by in early September of '84. In a killie trivia and care contest Alf would run away from us, but in that instance Kurt and I both suggested some sort of iodized salt.

Al grabbed what I thought was too much rock salt of the sort used in water softeners and tossed it in (the five or ten-gallon tank) with the observation that they would either die or be cured. We didn't count on the amazing ability of Cyprinodon to tolerate water changes, especially in the direction with a greater TDS. By the time we left an hour or two later, the swelling in their throats had gone down and they were busy doing their "feed me dance" at the front of the aquarium.

When showing a first-time guest around, a pupfish tank is an early visit (even near the floor) because they can be depended upon to put on a show.

Editorial comment: Even as a history person (as opposed to anyone with a chemistry, biology, medical or scientific background) it seems to me that the tradition of urging aquarists to use non-iodized salt in some books is one of those hobby myths we need not pass around. Certainly most killies, as "secondary freshwater fish" should have a tolerance for the ingredients in marine water, if the ingredients are added in moderation. A huge jump in mineral content (TDS) isn't good, but that is an osmotic pressure issue about the total amount of "stuff" suddenly added to the aquarium.

There is so much to learn or re-learn in this hobby. If we haven't learned anything lately, prolly we just haven't been paying attention. :)