When already established fish start dying for no apparent reason you should first check for the following:

1. Test your water for pH and Ammonia.
2. Observe your fish closely for signs of a fungus or tiny white spots that look like salt. (Ick/Ich)
3. Is your water temperature correct for the type of fish you are housing?
4. Watch your fish, especially at feeding time, for an hour or so. Do you perhaps have a bully fish in there that is perhaps chasing or harassing the other fish?

Did you recently do a water change? Did you add chlorine remover? Did you add water the same temperature as what was in the tank already? You should ALWAYS add water no more or no less than 2 degrees different from the current water temperature in the tank. If you did a recent water change and put chlorine remover in and added the correct temperature water, then you have a bacterial infection going on. When everything seems to be fine, I ALWAYS treat the tank for a bacterial infection. NOTE: A bacterial infection will sometimes show up as a clouding in the eyes.

If you lose fish within a few days of purchasing them your fish may have died from the stress of moving them. The fish are moved from their existing tank, put in huge bags, very overcrowded, shipped in a truck usually clear across the United States, taken out and put in a new tank. This is VERY stressful to the fish.

Another possible cause is putting them into a new tank where the water chemistry is different. Your water chemistry will obviously be slightly different from what they are used to. In newly purchased fish they have been put in 3 different types of water. The water they came in, the water at the fish store and then the water at your home. All of this within a few days.

A large difference in water temperature can be a factor as well. I have found that with the feeder Goldfish that I buy for my fish that only eat live food. I always lose a few the first few days. (I buy 100 at a time) The pet store I get them from has their tanks at 78 degrees and my feeder tank runs around 65 degrees.

Ask you fish dealer what day he receives his shipment of fish. NEVER buy fish on the day they arrive at the store. They are very stressed from shipping. It is best to wait at least 3-4 days after arrival. The fish that were severely stressed will have died already. Thus, the fish you buy will have a higher chance of survival.

Choose a fish store that has a guarantee on their fish. I am VERY hesitant to purchase fish from a store that offers no guarantee at all. Most reputable fish stores will offer at least a 24 hour guarantee. The fish store that I purchase from offers a 30 day guarantee.

When going to the fish store observe all of the tanks. Are all the fish swimming around and look healthy? Are there a lot of dead fish in the tanks? Do you notice any fungus or white spots on the fish? Are their fins clamped or jagged and torn? Don't just check out the tanks of fish that you are interested in. Check ALL of the tanks. Spend some time looking at each tank. Don't just glance in and move on. NEVER buy from a tank that has unhealthy looking fish in it.

While visiting various fish stores strike up a conversation with other customers. They are a wealth of information. Find out where they buy their fish from, where they have the best success in purchasing, and most importantly of all, what store they experience the most loses from. We have one fish store in town that we purchased from when first starting. We NEVER had a fish that lived past 24 hours when buying from them. They offered no guarantee either. Being new to the fish hobby we thought it was something that we were doing wrong. Since that time we spoke with other fish hobbyists and found out that this store has the worst reputation around. They have very unhealthy fish. One example was one day we went in and were looking at an entire tank full of Dalmatian Mollies (about 50). The next day we went back to buy 2. The tank was empty. We did not think to ask what happened to them, assuming they had sold them all. Had we been experienced we would have known that the fish had more than likely all died. So, talk to other fish hobbyist in your town. They can save you a lot of heart ache and money.

If at all possible, put the new fish in a bucket with the water that he was bagged in. Take water from your tank and put it in the bucket. Add only enough water to be the equivalent of approximately 1/10th of the amount of water in the bucket. Every 15 minutes add the same amount of water out of your tank to the bucket. If you have the time, do this for around 2 hours. By that time you will have replaced most of the water in the bucket with your water. The new fish will be adjusted to the new water. If you do not have the time to do this for 2 hours, do it as along as you can. Any amount of time is better than none at all.  NOTE: If you do not have a bucket, any large container will do. If you run out of room for water, you can take out the same amount as you put in at that point.

If you do not wish to do the above, make sure that you float the bag the fish come in, in your tank for at least 20 minutes so they get adjusted to the difference in temperature. Temperature is probably the most critical of the factors.

Once the fish is placed in the new tank, observe the other fish. Pay close attention to see if the other fish chase the new fish around. Some amount of chasing around is normal. The fish need to get their pecking order in place once again. However, if the new fish is being attacked as well as chased continually, the chance of the new fish surviving this aggression are very slight.

The first medication I suggest is CopperSafe by Mardel Laboratories. If you use nothing else use CopperSafe. It is a very good all around treatment and can be kept in there for a month. I like it a lot and have had good success with it. CopperSafe treats for the following diseases: Ick, Flukes, Anchor Worms, Velvet/Protozoan Diseases and other freshwater parasites. In addition to treating these diseases it also aids in stimulating the appetite in sick fish.

I strongly recommend that you use CopperSafe for the full 30 days. Many times when a fish is sick it will pick up a parasite because of its weakened condition. Parasites are ALWAYS present in your tank. I have heard that some fish hobbyist keep CopperSafe in their tank all the time as a preventative measure. I would not recommend doing this however. The parasites will build up a resistance to CopperSafe and it will not be effective against them in the future.

You add the CopperSafe to the tank only one time. If you do a water change during the 30 day period then replace just enough CopperSafe to get it back up to full strength. CAUTION:  Too much copper in the water can be deadly to your fish. When you add more CopperSafe to bring it back up to full strength, guess on the low side. In otherwords, if you think you took out 10 gallons of water, add the amount of CopperSafe for 8 gallons. It is better to err on the low side than the high side.

Whenever I suspect a bacterial type disease I ALWAYS treat with an antibiotic. I use either or both Maracyn and Maracyn 2. Though the names may make you think that these are the same medications they are really quite different. One treats gram POSITIVE bacteria and the other treats gram NEGATIVE bacteria. As in humans fish can get either type of bacterial infection.

I ALWAYS use all of these products for at least 7 days even if the appear to be cured. This is very important! I relate this to our own medications that the doctor gives us. A doctor rarely gives you medicine for less than 7 days and most often 10 days. It takes that long to get every last little bit of the bacteria that lingers on. I also used to be on a farm and raised many different kinds of animals. The same held true there. Always give a medication for a minimum of 7 days and I recommend 10 days. By giving a medicine for less you can end up having a bacteria that becomes resistant to the drug you are using and it will no longer work for you. If you are still experiencing deaths, continue on for a full 14 days.

I keep salt in all my tanks at all times. Ick does not like salt. Thus the salt works as an excellent preventative. I don't buy salt at the pet store because it is way too expensive. I buy regular table salt at the grocery store. Make sure you use only NON-IODIZED or PLAIN salt. The iodine will kill the fish. I use 1 tablespoon per 5 gallons of water. The salt also aids in the repair of damaged fins, etc. It is a really good thing to use. Your fish do not have to be salt water fish to use this. Regular tropical fish are just fine with it. It does not hurt them at all. When you do a water change, replace the amount of salt that you would need to bring it back up to full strength. In other words, if you take out 10 gallons of water, then you add 2 tablespoons of salt back in. Do not worry if you might get a bit too much salt. It won't hurt them at all.

DO NOT dump the salt right into your tank if you have fish in it. We did something that almost killed our Tire Tread Eel, Mic. Mic tends to burrow under the gravel and since he's a brownish color he is very hard to see. We did a water change in our 50 gallon tank and I was adding the chemicals and the salt to it while my fiancee was filling it with water. I started dumping the salt in and never noticed that Mic was right under the gravel where I was dumping the salt until it was too late. All the salt landed right on top of him. He was getting burnt. He went into convulsions and curled all up. I thought I killed him. We directed the water right on top of him and after a bit he started moving around and swimming erratically. That was about a year ago and he is back to normal now. So it is very IMPORTANT the you either dissolve the salt in water before you pour it in or wait until the tank is full before you add it and make sure no fish are in the vicinity.

Remove the charcoal filters from your tank or the charcoal will remove the medication. When your treatment is done remove as much water as you safely can and put your charcoal filters back in to remove the last remnants of the medicine.