fish suddenly dropping dead

Question
QUESTION: We had four fish one for about almost 3 years, one for a year, and a couple for almost 2 months. Then decided to add a cat fish and aquatic frog. A couple days later we added a Xray fish, two snails and another fish to our tank. There was not enough room so we decided to get a new tank with new gravel, water minerals,a decorative flower and filter. The day after the fish that we got with the Xray fish died. So later that day we got a new red eyed tetra. Around 12:30am we found that fish was dead. Suddenly they all just started dropping one by one like a domino affect. In five minutes five fish were dead (not exaggerating). Our two oldest fish were still there same with the cat fish,frog and snails. We immediately took them out of the tank. The one year old pink guppy went down 15 minutes after the rest.  We moved the remaining living fish into a clean fish bowl with clean water and the water minerals that we used before the new minerals. The cat fish didn't move that much but if you poked it,it did but it also slowly died. Spongebob our yellow guppy of almost three years lasted the longest and is now just floating in one spot. For some odd reason the frog is still alive. We know earlier today that too many water minerals were put in. We also just got a new tank,new gravel,and new decorations today along with a new fish. This does not explain how they all died at the same time. Before they died they would swim weird upside down and just stop. Please tell me why this happened.

ANSWER: Kelly,

I am sorry this has happened. Before i answer this question, i need some more information.
1. What size tanks do you have. The one that already had fish and the new one you bought.  
2. When you bought the other tank, did you rinse it out with very hot water along with the gravel and that flower?
3. on the new tank, did you cycle the water for 2 weeks.
4. Before you added the new fish, did you have them in a quarantine tank for at least a week.
5. Did you buy all the added fish from the same store?

I always tell people, that before they add fish, you want them to be alone to make sure they aren't sick. Disease travels fast in an aquarium. Its always good to have a quarantine tank they come in very handy. When you bring your fish home, float them in the tank its going in, with the fish still in the bag for at least 15 minutes. I know people that add a little of the tank water to the bag, but I don't do that. I also do not add the water the fish came in into the already set up tank. If the tank the fish was in, in the store is bad, then you don't want to add that water to your tank. I will assume that is most likely what happened.
I will tell you this has stumped me a bit, but I would also like to say. If you have a fish that has died in a tank, remove it immediately. DO NOT ADD ANY OTHER FISH TO THAT TANK. I think  there was a problem with the fish you added to the tank with the 4 original fish. Some stores that sell fish, don't check the water to make sure its ok. I have seen tanks that have dead fish in them and the people working there don't remove it.

I would clean out both tanks very well and then start from scratch including the 2 week cycling.

Let me know about my questions and together we will try to figure out what went wrong.



---------- FOLLOW-UP ----------

QUESTION: We have a 2 1/2 gallon tank and a 5 gallon tank

Everything was rinse with hot water.

We did not cycle for two weeks.

We did not quarantine the new fish.

they all came from the same store except the comet that died the night before the other fish.

would these mistakes make the fish die all at once?

Answer
Kelly,

Well, any one of these alone might not have done that, but if you have a few of them, then there will be a problem. As far as the over crowding, the best way to make sure that doesn't happen is to remember, for every inch the fish is, it needs 1 gallon of water. ie: a 1 inch fish= 1 gallon of water. a 2 inch fish needs 2 two gallons of water etc. An aquatic frog, needs at least 10 gallons of water. As far as cycling goes that is a must. If that doesn't happen, the water could get clouding causing the water to be toxic. When you cycle you establish bacteria in the filter that digest ammonia and turn it into Nitrite. Nitrite is more toxic that ammonia.The filter turns the Nitrite into Nitrate, which is relatively harmless.  Some people say you can add fish to the tank during the cycling and that,s ok if you use the right kind of fish. When I cycle a tank, there are no fish in it until the 2 week cycle is complete. Because you have small tanks, only put in 2 fish in the 5 gallon and 1 fish in the 2 gallon if you choose to cycle the tank with fish. DO NOT cycle the tank with goldfish unless that is the only fish you are putting in there.  Goldfish are a cold water fish as tropicals need heaters. The care for the goldfish is also different and if you put the tropicals in then the goldfish can stress out, and your tank might recycle itself. Fish that you can put in the tank while cycling are: Zebra Danios or  White Clouds. If you want more of an aggressive tank Cherry or Tiger Barbs are good.

This is my guess on what happened. Not cycling the water coupled with not quarantining the fish is most likely the main problem. The fish, all but 1, bought from the same store. I might suggest going to a different store to buy the new fish. I am not sure, but if you added the water that came with the fish into the tank, that too could have helped the problem.

This is what i would now now.
1. clean the tanks out very well with a bleach and water solution. 1/2 cup bleach. Fill the rest of the tank with hot water.
2. allow tanks to dry outside in the sun. That will help the evaporation of the bleach. If you want to know if the bleach is gone, just use your nose and smell the tank. If you smell bleach, then the tank isn't ready. Make sure after, using the solution, you rinse well with very hot water.
3. Also clean all the gravel and whatever decorations that were in the tank.
4. i would change the filter in the tank, fill it with water and cycle the tank for at least 2 weeks.
5. While you are cycling the tank, buy your fish and put it/them in the quarantine tanks. That way when when your aquarium is ready, you will know that the fish are healthy and can be placed in the main tank. I would buy 2 fish and do not place them into the same QT.
6. I would not add more than 5 small fish in your 5 gallon tank and no more than 2 fish in the 2 gallon.

If all the above is done, then you will have a very happy and healthy bunch of fish.

I hope this helps, and don't hesitate to ask if you have any other questions.

Good Luck