all my fish are dead but 3

[ladynash]

ok I have a 20 gallon tank that has been set up 9 months and was having a few little problems with what I thought was ich but was treating them and they seemed to be doing better 3 guppies and my panda cory cat seemd to do better but I started seeing tiny white or clear worms in the tank. So I did a really good cleaning of the tank and bang over nite 2 of the guppies died and my other doesnt look so good.
Well I also have a 10 gallon tank been set up for 5 months that I had 3 guppies and a green cory cat in it. I did a routine cleaning of the tank and over nite 1 guppy and the cory cat died. I suspect my water as it was the only common factor and was done the same time. I did it like always I got my water ready and added my aquasafe with bioextract like I always do, could something be wrong with my water all of a sudden it is fall and I did read in the paper they had worked on the water and tested it all and we passed but that makes me wnder if the added something to it. My fish in the 10 gallon tank were not sick and were very healthy and the tank looked clear and fine.
 I was worried about the 20 gallon tank because after the water change it looked cloudy and the worms made me clean it again so I could really do a good gravel vaccume. I do know that tank had alot of snails( trumpet) they kinda went nuts and were really populating but I read I was feeding too much so had cut back and was trying to clean up the tanks.
PLEASE someone I already lost 1 beloved cory cat and am worried about " cat daddy" whom I have had for months ( I have decided they are my favorite fish so far.
Should I buy water to use or what.There is spring water or distilled ect? PLEASE someone help me figure this out.
Donna

[Yipee]

Have you tested your water for ammonia NitrAte and NitrIte? Spikes from any of these could be lethal to your fishes. You should phone up the company treating your water and ask them if anything was added just like what you suspected.
Just in case you decide that you will have to clean the whole tank and use either mineral water or distilled water, use distilled water. There are minerals salts in mineral water that makes it hard. If you do not have any test kit, bring your water to your Local Fish Store to be tested for Ammonia, NitrAte and NitrIte.

[Yipee]

And I forgot to mention those tiny white or clear worms you mentioned is not Ich so you kinda use the wrong treatment. Are they worm-like or water leech like? The white water leech type could be Planaria. Hopefully you might be able to post a photograph.

[wendyjo]

Distilled water isn't good to use unless you add back the minerals that are removed in the distilling process.  Fish need those minerals.

[ladynash]

ok I gave the wrong idea. I do test and my NitrIte and amonia are in good shape and the ich I suspected was from salt like substance on the fish themselves not the worms they are an added thing and are in both tanks. I did alot of reading and at first thought they were due to over feeding which I am guilty of without question.
I turned the light on the 10 gallon tank and saw the worm like creatures everyplace so they must like the dark and get active no idea. Guess I am gonna have to take down both tanks and start over with new or very clean gavel which is what I use.
My new question is can you buy and safely use spring water or like walmart water in the gallon jugs.
I suspect my water because the 10 gallon tank were very healthy and thriving and happy swimming fish and now 24 house after a tank cleaning like usual all but 2 are dead in that tank. They were fine I cleaned the tank and went to bed and got up to dead fish.
It was the 20 gallon I thought was sick but were making a great comeback and doing well eating good ect then I cleaned and did so the same night( I always do routine cleaning the same night) and in the morning 2 were dead.
I called the water treatment and they said they always increase chemicals in the fall due to leaves and debre so I asked could they please tell me the chemicals and they said I could come get a report but it does not list individual chemicals on it so what water would you use if you were afraid of the tap water? What would you do?

I tried to take some pictures of the swimming tiny worm like creatures andjust could not get them to show up. They look like the worms on the sticky that comes from over feeding very tiny almost hairlike and srunches up and then opens and swims kinda sidewayes. dont seem to be after the fish.

[Morgrid]

Nematodes come from overfeeding and that is likely most if not all of your problem. Overfeeding is a very common killier of fish. Back way off on the feeding and do some frequent water changes with gravel vacuuming. The worms themselves are not killing your fish they are just a symptom of the decaying food. There are quite a few types of nematodes that will invade a tank, one of them is the threadlike swimmer you describe. If you care to look there will be tons more of these worms in the gravel. The other type commonly seen is a larger worm that crawls along the glass and other objects of the aquarium. If you are treating your water for cloramines, it is not likely that it is the problem, although exact water parameters would help us. It is hard to say about spring water bought from any source, many are listed as spring water but in fact are distilled water. Distilled water has no mineral content and will kill your fish fairly quickly. If you can get your feeding habits under control there is probably no reason to tear down the tanks.

[ladynash]

thankyou. I have been holding food now for 2 days to help I did read some information on the over feeding which made me know my error on that. I will go test my water in a few minutes and post what I find.My large tank is all cloudy looking after the change and vacume. I was thinking of doing it again as I now see no little swimmers but only 2 fish left in the tank because after the water change and cleaning all died except 1 guppy and my sweet cory cat.
In the small tank it is over run with the swimmers today and only 2 fish left. I just dont understand because that tank was not the least bit sick but I plan to clean. now I see a little algea on the back of the tank. Boy am I in a mess all of a sudden.
Everyone says not to get any other kind of fish but guppy because they are easy but I did far better with my cory cat than them. I kinda like some of the other kinds.
Now I am not sure if I clean everything up and get rid of the swimmers will my tanks be safe to add fish to. Any and all advice is appreciated. I  just really love fish and have 2 nice tanks a 20 and a 10 gallon I have a chance to have a nice set up to enjoy.

[Morgrid]

The algae is not a problem and will not kill your fish. The swimmers are also not likely a problem in themselves but do indicate the waste in the tank.

[Yipee]

It is not true that all fishes are more difficult to raise than guppies. You can try hardy tetras too. Although some people find neon tetras delicate, I think they are very adaptable to water parameters and diet, and ATTRACTIVE. Zebra Danio, Red Eye Tetra, Flame tetra, black widow tetra and cory cats like you said make good beginner fishes too.
For cory cats, it depends on the species. Panda cories and the flagtail cory which in new in the hobby, are sensitive to water parameters while others do great.

[wendyjo]

I've found that of all the fish I have the guppies are the least hardy.  I think there's been so much inbreeding with them that they just don't have the health that they used to. 

But that doesn't really explain the sudden deaths you've had.