I have a 30 gallon tank in which all my long-time fish have suddenly died in clear water. What's wrong?

Question

The fish were exotic goldfish and a pleco. How can I find out what to do to keep new fish from dying if I restock the tank. The water looked clean and clear when they died and no outside poisons got into the tank.

Answer 1

Did they exhibit any symptoms like bloating, frayed fins, white spots (ich) etc?

The fact that they all died indicates that something went wrong. Could some toxic have gotten into the tank? Ie did you reach into the tank after using soap on your hands? Or spray an aerosol can into the air? Or wash a tank decoration with bleach? Did you forget to use dechlorinator? Fish are very sensitive to water, and without even realizing it is possible to contaminate the water.

Do you do weekly water changes, and vacuum the gravel?
Goldfish and plecos are perhaps the two biggest waste producers when it comes to fish! They are poop machines and a 30 gallon is too small for anything more than two fancy goldfish.

You should invest in a testing kit (a master kit will cost you about 30$ and will be your best friend! get a liquid kit, not strips). Sometimes tap water changes sources in different seasons so you may have a high pH or something else in your water that may have harmed your fish.

Anyway, thoroughly clean the tank. DON'T use bleach, or any cleaning products. Rinse all the tank decor with hot water. You can use a 1:2 vinegar:water solution to disinfect the tank. Get a new filter cartridge.

Be sure to re-cycle your tank. Get some Bio-Spira or something, and please know that other products like Cycle which contain the dead cycling bacteria, and are completely useless. Only Bio-Spira contains the live bacteria.
http://www.worldcichlids.com/faqs/cycling.html

If you're going with goldfish again, please know that the max you can have in your tank is 2. And if you want a pleco, be sure to get a bristle nose, as they only grow to 5" as opposed to the common pleco which can grow 18-24".

Start with only one fish and see how it goes.

Answer 2

Get a test kit from your pet store or a place like Foster and Smith or a fish supply store. They make them that test for everything....ammonia, ph, nitrates, hardness of water, etc. The results of these will solve your problem. I have a cure all....it is called Melafix. I have found that it keeps fish very healthy and the tank in great shape. You can get it almost anywhere fish stuff is sold. Walmart has it, too. Good luck. Also, make sure you are doing atleast a 25% water change each month. Use dechlorination drops.

Answer 3

Many things can go wrong. The more common reasons are ammonia, or nitrates too high. high ammonia is a problem with tanks with many goldfish. It can be easily controlled by buying a ammonia removing pouch and placing it in your filter. It should be replaced once a month. Be careful not to be carried away with too many goldfish as they eat a lot and therefore poop a lot, creating the spikes in ammonia and nitrates. Most mayor pet stores will test your water for free.

Answer 4

Take a sample of your tank water into your local fish store. They have the means to test your water on site to let you know what happened. You can also buy a kit to do the same at home and keep it on hand. Good Luck!

Answer 5

Tank a sample of the water to a pet shop and they have equipment that can tell if there was something in the water. Cause it most have been the water...

Answer 6

As the water may look clean and clear but you should regulary check ph levels,nitrites,nitrates and ammonia as this is very important part of having healthy fish.

Answer 7

you can buy a great book called AQUARIUMS FOR DUMMIES. It tells about all diffrent kinds of fish diseases and ways you can treat them. it also has a ton of other useful info about keepung a fish tank. i bought mine at PetCo.If you can find it there you should check your local library or you can buy it online at www.overstock.com for 12.99. good luck!

Answer 8

i threw cheeze its in the water