Why is my fish dying?

I have a 3-4 week tank that had the proper amount of starting bacteria added. I'm pretty sure the tank should be at least partially cycled. I have a small shubunkin goldfish (1.5 in), and a comet. The first comet died in 3 days because of some kind of disease. I am to blame for that, because i did not read carefully, and didn't cycle the tank before I bought the fish (the shubunkin is still alive). However, what startled me is, the shubunkin started developing these white dots, and now its tail is getting all shredded on the tips. I added coppersafe, (I only added it once), and its getting worse and worse.
The most startling thing is, the pet store gave me a replacement for the comet. That new comet died in 6 hours. I don't think that is due to any disease or ammonia. The two goldfish stayed side by side for hours (seemed to like each other).

My questions are: What is causing my fish to die? How can I stop it? I really really don't want my shubunkin to die, so is there anyway I can stop it? My comet goldfish did not have a mark on it. It was pretty lively after I put it in, and then detoriated quickly. It had no white spots, no inflamed gills, nothing. I removed it from the tank today.

BY THE WAY, my pet store is PETCO, and they overstock their tanks like CRAZY. there were like some 200 0.8in comets in a 50 gallon tank. All their other fish (like shubunkins, tetras, gouramis, etc.) are all crowded into groups of 5-20 in 3-4 gallon tanks. I discarded the water that the store gave me, and used only my own water.


ARGH what am i doing wrong???

What "start bacteria" did you use? We asked that one before in your previous threads, and we didn't get the answer.

As I recall, your tank is undersized for even one goldfish. On the top of that, it is uncycled.
You shouldn't have had the replacement fish to make it two again after you lost your first one.

Your new replacement fish died in 6 hours, it can only be one thing - shock.
How did you introduce it into your tank?
New fish can't get used to your new water right away. If you dump it in, it dies quickly. Because the new water has different temperature, PH, hardness, etc.

This article talked about the most common reasons for fish dying quickly after sold. One of them is "shock", and there is solution to avoid shock in the article which is the proper way to introduce a new fish into the tank.
Reasons Behind Why Average Fish Die in 3 Weeks After Sold.

I would have stayed away from CopperSafe. There is nothing safe about CopperSafe. It's heavy metal. It is really hard on fish. The tanks had CopperSafe in it would never be safe for certain species of fish who are sensitive to heavy metal.
In fact, you shouldn't jump into conclusion and use medication before you can be sure what was wrong with the fish.

If you can share a clear photo of your sick fish, we might be able to identify the disease or parasite if there is any.

Pet stores like Petsmart and PETCO will always overstock their fish tanks. It is not economical for them to have only a few fish in each tank. Their fish come and go quickly, so they are not worried about a few fish dying each day. They never planned to keep the same fish for more than a few weeks tops. Don't learn from them if you plan to keep fish properly.

A picture might help better identify the disease if there is any disease at all.

From your earlier threads, we learned your tank is too small for your fish. As well as no filter at first, then the new filter was just in and certainly it was not cycled.

When we identify a problem for "dying" fish, the first thing we look at would be testing for ammonia and nitrite in the water. These are the #1 killers for new fish tanks. Unless there is clear sign of certain known diseases.

Please provide a good photo of your fish if you want a better diagnostic.

Did you figure out what the problems were and if the advice given helped? Instead of going to the big chain stores, find a local shop that only deals in fish. The owners and employees would be a better source of information than a hourly worker that's just watching the clock for lunch.

(05-22-2012 03:07 PM)rwzheng1997 Wrote:  I discarded the water that the store gave me, and used only my own water.
ARGH what am i doing wrong???

We buy new fish from our local vet/pet store where one of the assistants knows a lot about fish. The first thing she said to us was to keep the fish in the water they provided, and place the bag in the tank, so that the two lots of water mixed and the fish could swim out in its own time. It's not such a shock to the system then.

So that's one thing you're doing wrong. I think you're also rushing things. We were told not to even think of introducing fish to the tank for at least 4 weeks. Maybe before you get any more fish you need to do some research, and talk to an expert. It's not fair to the fish if they only last a day or two, because you can't wait to get the tank conditions right.

(09-18-2012 11:54 PM)Sandra Piddock Wrote:  We buy new fish from our local vet/pet store where one of the assistants knows a lot about fish. The first thing she said to us was to keep the fish in the water they provided, and place the bag in the tank, so that the two lots of water mixed and the fish could swim out in its own time. It's not such a shock to the system then.

So that's one thing you're doing wrong. I think you're also rushing things. We were told not to even think of introducing fish to the tank for at least 4 weeks. Maybe before you get any more fish you need to do some research, and talk to an expert. It's not fair to the fish if they only last a day or two, because you can't wait to get the tank conditions right.

Standard procedure to add new fish into the tank should be adding the tank water little by little into the bag. To let the fish get used to your tank water slowly. Once the bag is too full, get ride of half the water and add more tank water slowly. The whole process should take no less than one hour in my opinion. For some more sensitive fish species, it can take 2~3 hours with less tank water being added into the bag each time and longer wait time between each adding.

For new tanks that had never had fish, we need to do fishless cycle. It can take up to 6~8 weeks, sometimes it's much faster if you do heavy bacteria seeding. Simply "wait" will not do any good.