Newly added fish die in established 45 gal tank - help?

Question

I recently added 3 platys and 4 guppies to my 45 gal tank. I had 4 other small community fish. Less than a week later, only a few of them were still alive.

I tested my tank prior to adding the fish, them temp was 78 degrees, and all levels were good. What the heck. This seems to happen every time I add fish, could my filter be too small??? It said it was adequate for my tank...

I have had my tank up and running for several years, am getting tired of fish dying....I hope you can help.

Shari

Answer 1

It's difficult to pinpoint a cause with just the info that you give. Usually, though, if there's deaths, especially among new fish only, it's related to water quality. You don't say what exactly you were testing and the results, so it may be that you weren't running all the standard tests, and one of the tests you didn't perform may have been the cause.

Your temperature should be fine for any tropicals, so you should be able to eliminate that (as long as you're using a thermometer for the temperature reading, not just trusting the setting on the heater). If your tank was established, the ammonia and nitrite should have been 0 and nitrate should be below 40ppm. The pH should be fine anywhere from 6.0 to 8.5.

As far as your filter, for a 45 gallon tank it should be rated somewhere in the range of 225 to 450 gallons per hour (GPH). A little higher is okay, but you don't want to have it so strong that the fish couldn't swim normally.

My first thought was that the ammonia, nitrite, or nitrate may have been a little elevated, but your earlier fish may have become adjusted to that level, but the new fish weren't. They may have been the initial ones to die, then their added wastes and decomposition if you didn't find the dead fish right away to remove them would have increased the levels even further, causing some of the original fish to die.

Another possibility is that because you added new fish, you may have been doing larger water changes (or more frequent) than normal. This could be a problem depending on what your water provider uses to treat your water, and the conditioner you use. In the past, all companies used chlorine, which could be removed just by letting the water sit for 24 hours. Because the chlorine doesn't last long, more companies are switching to chloramine, which combines chlorine and ammonia. If you use a conditioner that only removes chlorine, or one that "breaks the chloramine bond", you're releasing ammonia into the tank. This can also be fatal to your fish. You can call your water company's ofice to find out which product they use.

Did the fish show any signs of discomfort (gasping at the surface, loss of appetite, scraping against objects int he tank, etc.) before their deaths? This could be a clue as to what may have happened.

Are all your fish livebearers? If so, try adding a small amount of non-iodized salt to the tank. About 1 tablespoon per every 5 gallons of water. I had a breeder tell me to do this for guppies and I've had less losses. Even though they're thought of as "freshwater" most livebearers prefer a little salt. Other fish will get some benefits as well, and the level I suggested is even low enough to use for tetras, which tend to be sensitive to salt. Just add the salt to water and let it dissolve before adding it to the tank.

Answer 2

Do you use tap water, I know it is kind of an obvious thing that tap water shouldn't be used, but I'm just trying to cover everything. Also, I know that places like wal-mart don't have very reliable fish, I often go there and see a multiple dead fish in a single tank. You should go to petsmart, they usually have very reliable fish sources, an okay selection, and a 14 day warranty for your fish. Just put the dead ones in a plastic bag and return them. Another thing to consider is if you are letting the bag float in the tank long enough, maybe you need to let them stay in there for longer. Try a half hour to an hour, and after half of the time, mix some of the tank water in the bag and close it again.

Answer 3

Have you tried getting your fish from another source? Sometimes the mass merch. stores sell sick fish. I would check your waters ph level or bring in a sample and have it tested. If all else fails try a bigger filter. If you add water make sure it is not right out of tap too. Other than that I don't know what else it could be unless something is getting into your water like a chemical of some kind. Good luck and I hope you find the answer your looking for.

Answer 4

If it keeps happening to you everytime you put in new fish, how about try to learn how to acclimize properly.

Step By Step:
When you get to your aquarium, you should open the bag and fold the sides of the bag for about 30 minutes in the water. After about 30 minutes, get a cup and fill it water and pour half of the cup in the bag. The rest your put back. Wait for 10 minutes and then do the same thing again 4-5 times. After this, you get a container and dump the bag in it and scoop out your fish with a fish net and into the Show tank!

Good Luck next time!

Answer 5

The fish may just be stressed. I have had the same problem with platys and mollies dying off in my 30 gal tank. It seems to help if you add stress chemicals to the water when you add new fish. Try stress-coat and stress-zyme. It's also a good idea to use an appropriate amount of salt to treat the water each time you change out some of the water in your aquarium. The aquarium salt is cheap and it really does help keep your aquarium healthier.

Answer 6

Are you emptying and refilling the tank regularly to keep the oxygen level up? I have a 55 gallon tank and I have two filters in it, both are for 20-40 gallons. I figure more is better...that's all I can think of...hope it helps!

Answer 7

Most of the time when fish die within a week it is because the ph level is different than what they were accustomed to.

Answer 8

did you choose good quality fish, or just pretyt ones? one want fast moving energetic fish

maybe you should ask the owners of the fish shop theph levels, sp you can make your wter as similar to theirs as possible

good luck!

Answer 9

Did you accliment them? I lost many of my first angelfish NOT acclimating them the right way or not at all. Read up on how to do it and if you did accliment them, I dont know what to tell you.