Aquarium Water

Question
We've had our new aquarium for about 6 weeks now and things were going pretty well until about a week ago. We started with 2 small goldfish, 2 other small fish (I don't recall the type) and 2 snails. One of our goldfish died 2 weeks ago. We had just done a 50% water change about a week before it died.  After the goldfish died, I tested the water & it showed high levels (nitrate, nitrite, hardness & PH but normal level of chlorine)  Now our two snails have also died about a week ago. I'm not sure what I need to do differently. Do I need to add some water treatments and if so, what kind? The only water treatments I have are the Aqua Safe for new water.

Answer
Hello Kandy:

Sorry to hear about your fish loss.  How big is your tank?  There are a couple of issues that I am just going to talk about in general here and I hope that everyone who reads this response takes this advice to heart.  Pet Stores will not always tell you that Goldfish and tropical fish should not be mixed together in a tank.  Goldfish are cold water fish and tropical fish are warm water fish...so never mix the two.  Also; water changes never need to be greater then 30% at any one time unless you have an epidemic or the chemical balance of your tank is extreme.  When keeping an aquarium the goal should be to find the best balance for what you keep in your tank and this balance includes bacteria... there are good and bad types of bacteria... Large water changes will throw off the tank balance and cause the balance between good bacteria and bad bacteria to become one-sided.  If your fish are dying in this tank  you should probably remove the ones that are left if possible.  If it is not possible to remove your remaining fish then I would go to the local aquarium (im pro aquarium and con department store when it comes to supplies and fish) and get a product called CYCLE. There are other products that do the same thing and most of them are probably equal in terms of result... so if the aquarium doesn't have CYCLE then get an alternative.  These products will help to bring your tank back to a normal chemical balance.  Make sure that you are gravel vacuuming the bottom of your tank.  Nitrates can come from over feeding your fish as well as fish waste like feces or urine.  Keeping an aquarium requires that we clean our tanks... it is unrealistic to expect a snail or cleaner shrimp to keep a tank clean.  Also when it comes to feeding your fish provide no more food then what they can eat in about a three minute period.  I feed my fish twice a day and once in a while I provide a mid-day snack such as a few brine shrimp.  Goldfish are constantly looking for food even though they are not hungry... so don't be fooled by their begging nature.  Feed only what your fish can eat within three minutes of time.  Make sure that your filter is clean... change the filter whenever it becomes dirty. If you are using a bio-filter then just clean the changeable filter... the inner sponge will house good bacteria so you may just want to give it a lite-rinse if it looks really gross. If you are adding tap-water make sure you have a dechlorinator.  I know this answer sounds kinda harsh and its really not meant to be harsh but at the same time I want to prevent future fish death.  If you have further questions I am happy to answer those as well.  Dave