Reptile & Amphibian Forums

I'm new here, but I have a few questions about my recent problems with sick fish.

I've had a 30 gallon aquarium since May 2007. We kept a few tetras, zebra danios and gourami in there with no problem for about seven months. Then, I bought three clown loaches and three white tetras, and everything fell apart! The three tetras died within two days of purchasing them with the clown loaches close behind. Then, all of the other fish followed along until we were left with only two serpae tetras. When the fish started dying, I took a water sample to the store to see if something was wrong with it, but everything tested normal. At the time, we also had a snail infestation (from buying real plants), and whatever killed the fish killed all of the snails, too.

After the fish died, I cleaned the tank thoroughly (80% water change, boiled the decorations, removed and threw away all live plants, etc). I let the tank sit for about two months with regular water changes of about 15-20% weekly, and the two remaining serpae tetras stayed healthy. After two months, I did another 50% water change, and then bought three silver dollars and a parrot cichlid a week later. We just bought them on Sunday, and yesterday (Tuesday), the parrot cichlid began head standing (floating/swimming around with his head down and tail up), and I noticed that one of the silver dollars has white "stuff" on him. It doesn't look like ich, it looks more like peeling "skin" or white strings of fuzz. All three silver dollars also appear to have ragged edges on their fins, but I can't tell for sure if it's new or if they already had that when they came - I did see one of the serpae tetras nipping at one of them when I first put them in. I did another 20% water change last night when I noticed that the fish looked sick, but they still looked sick this morning.

They have plenty of oxygen, and ammonia levels are fine (I have an ammonia reader on the side of my tank). I plan to take a water sample into the store to test nitrites and nitrates, but what else can I do?? I'm not sure how they got so sick in just two days! We were hoping to upgrade to a 50-75 gallon tank later this year, but we don't want to make that kind of investment if we can't keep any fish alive!! The store will take the fish back if they die within 14 days, but I'd much prefer to find out why they keep getting sick so I can keep them alive!! Any suggestions or advice would be appreciated!!

I should also note that we use the recommended amount of freshwater aquarium salt with each of our water changes as well as Stress Zyme to remove chlorine and protect the fish.

first question I have is did you buy your tank new or used? because if your tank has been used for anything other than fish that might be your problem... another thing you are changing your water alot I would only add water to your tank when it is low and if you do reg. water change only about 10% water change each time dont do a 50% water change it stress your fish out you have to think that is there home you are changing they get use to the things that are in the water so when you change it alot they dont do as well. last thing I can think of since you are already using salt is I would use aquasafe as my water conditioner I think its the best kind hope this helps

Now I've read just the opposite in The Simple Guide To Freshwater Aquariums by David E. Boruchowitz. He says the more often and the more water you change the better off your fish will be.
staffordmom

well you can do what the book says if you want but when you change that much water on them they cant tolerate it as well a lil at a time is ok like once a month but me I mostly just add water and clean my gravel to change water and my fish do great and even better since I started using salt...but I wouldnt do a 25% change and a 50% in less then to weeks that means your changing almost all the water in the tank it leaves none of there normal habitat you should look up on the net about changing your water I'v always found more on the net then trying to find it in a book I hope I'm helping and not making things worse oh and like I said if your tank has been used for animals before fish that also might be the problem

It is true that you should only change your water 10-20% every two weeks. Like izzy said, it will mess with the bacteria.
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Phishie

"An ounce of prevention is worth a pound of cure."