Unidentified fatal parasites?

[LaceyMae]

15-20 gal common setup for freshwater tropical
undergravel filter and charcoal pump/filter
gravel, two fake plants, fake log and jug
fed tropical flakes
a pleco(?) algae eater 5 yrs
3 chichlids I've had for (?) years

I did a compete water change as I've done a couple times before. I did get new gravel and add the fake log. I treated the water, had ph ok, temp ok, and put the fish back. Everything was fine... two weeks later, they started hovering at the bottom and I noticed algae eater with cloudy eyes. I treated with melafix for bacteria or fungus and they kept getting worse. Spots, cloudy eyes, slimey gray/white film and then they died off very quickly. No open wounds or gashes. The algae eater started bashing against things and convulsing. Looked like nipped fins, on all of them too. The last chichlid died yesterday, and as I peered into the tank I noticed these VERY small, thin, white worms. They "glide" across the glass and do not crawl in any "s" form. I've read about all kinds of things like this, but can't find what this could be. There are so many of them, and I don't know what to do. Can anyone advise? What are they? I don't know how to get rid of these and start anew.

[wendyjo]

You gave us alot of info, but left out alot as well.  Please read this and answer all the questions, especially the ones about your water parameters and tank maintenance.

The worms probably did not kill the fish and I suspect a possible bacterial problem possibly caused by poor water quality.  But without knowing the water parameters, size of the fish, and your maintenance schedule it's really even hard to give an educated guess.

Also, when you say you did a 100% water change, are you saying you removed the UGF and gravel as well at that time?

[LaceyMae]

I will tell you first off, that I'm not a very advanced fish keeper. Parameters? I've never gotten that in depth. I've just always done what I've done and never had any real problems. Until now :^(  ...I keep the Ph around 8 and I have no heater... room temp has always worked for the freshwater tropicals I've had. The pleco was about 4 1/2 to 5 inches. One Cichlid was about 3 and the other two one about 2 inches and the other somewhere in between. Yes I did remove the filter and gravel... I changed the gravel and rinsed it well as I always have. As far as maintenance goes, I usually vaccuum the gravel when I can see yuckies. Once every week or two. If it's bad then I will do a partial water change (usually 1/4) If not, then I will give it another week. Sometimes if all is good I will go a month before doing a partial. A partial is usually 1/4 to 1/2. I have gone a long while with no partial and everything be fine... and I've done complete in the past with no problem.. I'm so bummed!

BTW - I've looked at so many charts and pics of the bugs and such and haven't seen anything of the sorts... I really need to know about those. I think you're right about the bacteria killing the fish and I was using the wrong treatment... Oh, buggers! The worms have to go...

[Ppulcher]

With undergravel filters, the gravel itself becomes the biological filter where all the good bugs that eat fish waste live.  When you took the gravel out and rinsed it, you probably rinsed out a lot of those good bacteria. I'm guessing that when you assembled everything back again, there were not enough good bacteria and the fish were affected by the ammonia - essentially starting the tank from square one.  You may want to have a quick read about "cycling" a tank.  Using a supplementary filter that you clean at alternate times might help.

[wendyjo]

I agree.  The fish probably suffered from ammonia and/or NitrIte poisoning because you destroyed the cycle when you cleaned out the gravel.  Filter media, whether it's a sponge, foam, ceramic pieces, or in this case the gravel, should never all be cleaned or replaced at one time.  That removes the beneficial bacteria that breaks down the ammonia and NitrIte into less toxic form.

I also agree that you should do some research on cycling the tank and proper maintenance before you set the tank back up.  There is a sticky article in the Basic Aquariums 101 board on cycling, and if you do a search you should find alot of info about maintenance.  I believe there is a thread going on right now about maintenance in the Fishkeeping Debates forum.

[LaceyMae]

Thanks for the advice on cycling. I've read up on it, and now I understand what's really going on in there. Never had thought much about it considering the years I've kept an aquarium, I've never had any problems... but then, I don't guess I've done COMPLETE changes.. or changed the gravel, at least. Anywhoo... what about the wormies? Any ideas what they are? And how to rid them?

Being you guys are definitely more knowledgeable... what would you advise:

Treat to kill the strange things... and test the water to allow this current cycle to complete? (being that there's a current process in progress) Oooor... empty, clean and start ALL over?

Thanks again!

(and oh, I see I have a fellow metal head?  )

[wendyjo]

Id' start all over.  If you don't have any fish in there or a source of ammonia then the tank isn't going to cycle on it's own.  Read up on fishless cycling.  Empty the tank, clean it well, then start over and do a fishless cycle.  Maybe upgrade to a different filter than an under gravel as well.

[LaceyMae]

Well, the fish were in there for a while. It went through a "smell" - and that means ammonia, right? lol... great way to put it, aye? I do have another filter/pump. That's what circulates and helps aerate. It has a charcoal cartridge as well as a bio cartridge. I have that along with the undergravel. That may be why I've never had much of a problem before. The bio was pretty well established too... had a good bunch of build up on it... but I replaced that cartridge, too. I never knew what that was for... so now I feel like a REAL smarty! Kind of funny, I guess. I really have learned alot. You guys are great.

If I need to start all over, I will. But I'll still test out of curiosity. I just wanna know about the uninvited guests... kind of creepy...

[wendyjo]

Typically you can't smell the ammonia in a fish tank. 

Really you should just start over.  There is pretty much a nil chance that there is any type of biological filtration going on in the tank at this point.  And starting over will get rid of the unwanted critters in there as well.