My tropical fish keep dying!?

Let's start with something simple like chemical poisoning. Did you clean the tank with anything but water before you set it up? If so then your tank is ruined and can never be used again. Even the smallest amount of chemicals will kill the fish and are nearly impossible to completely remove. Both the tank and any equipment you use in the tank (including your water change bucket) can not have so much as a hint of chemical contamination. That means they can never have had chemicals on or in them at all. Also, never spray any chemicals near the tank.

If you can rule out chemical poisoning your fish may be being poisoned because you stocked the tank before it was cycled. Also, looking at your water parameters (8.4 pH, 300 alkalinity, holy crap, that's liquid rock!) the new arrivals may be dying from shock since it's doubtful that the water in the bag they came in is anywhere near your water parameters.

First the cycling:

Every new tank needs to go through a cycle, that is the time involved for it to build up bacteria in the biological portion of the filter that transform ammonia to nitrite and nitrite to nitrate. Both ammonia and nitrite are poisonous to fish; the nitrate is benign until the levels get up to about 40 ppm or so. The best way to cycle a tank is through a process called "silent cycling", which involves using pure ammonia to cycle the tank BEFORE any fish are added. Once cycled in this manner a fairly large bioload (i.e. fish) can be added to the tank. Google "silent cycling" or "fishless cycling". You should never use fish to cycle a tank as it is cruel and leads to unneccessary fish death.

As for acclimation, it's best to slowly acclimate the fish to their new environment:

1) Turn off lights in the tank and any bright lights in the room.

2) GENTLY transfer your fish and the water they came in from the bag to a container that has never seen cleanser. I like to use a plastic gallon water jug from which I've cut off the top.

2) Using a length of airhose, tie a couple of loose knots in it then start a siphon from the tank. Tighten the knots until you get 2-3 drips per second from the hose.

3) Put the drip end of the air hose into the container. When the water has doubled in volume, remove half of the water.

4) Wait until the water has doubled in volume again GENTLY net out the fish and transfer to the tank.

5) Leave the lights out for at least 2 hours to let the fish get accustomed to their new home.

Even with proper acclimation the water you have is WAY too hard for some of your fish, most of them except for the Mollies (they like liquid rock). I know that you and your mom are anxious to have a tank but being an aquarist is an involved hobby. You can't just run out and get fish. Even after cycling you should know what kind of fish you are putting in the tank and their requirements. Soft water? Hard water? What are their temperature requirements? What kind of foods do they require? Are they live bearers? Egg layers? Are the species you are putting in compatable, not just in terms of temperment but also water quality? Are they schooling fish (4 Tetras? Shame!) Are they solitary creatures? Without further knowledge, from books or even from reading articles on the net, you will only suffer more fish death, become frustrated with the hobby and eventually just give up.

PS (Ditch the undergravel filter. They just get clogged up with detritus. Invest instead in a really good canister filter from a reputable manufacturer like Eheim)

Pretty much the same thing as everyone else said. When I recently got a second tank for Christmas (15-gallon) I was SO EXCITED to put fish in it but had luckily done some research and waited a good week before adding any fish. Eventually, I transferred just one gold barb into the tank to help the cycling process along, and checked on it every few hours to make sure it was fine. It did really well, so I added my other gold barbs along with it about another week later. After another 2 weeks I moved my paradise fish and blue gourami over to it. I've never had a fish die from water quality in this tank yet.

So yeah, just make sure to add your fish slowly, not like 10 at once. Pretty much if you add a ton and everything isn't just right yet, the addition of all the new waste will make the levels in your tank go crazy.

That and your pH of 8.4 might be a little too high, but then again I'm not sure the specifics for the fish you've got :/ If in doubt, I'd go for a neutral 7.

You say you have a new fiulter did you seed it with old filter media ? if not you could be goiing through a nitrogen cycle again , test your water for Ammonia , Nitrite, Nitrate, & pH , pH below 6 will hold ammonia in a non toxic form but when it gets up past 6.0 it will release the ammonia back into the water column as toxic ammonia this will burn the gills of the fish and then its a downhill path for the fish. High Nitrite levels will also kill fish quickly, check for food etc that is decomposing in the tank it will turn the tank rapidly. These 2 are the most common reasons for fish loss if no disease is suspected, adding meth blue can take out oxygen from the water so added aeration is recommended.

You are putting too many fish at once. You aren't supposed to keep Tiger Barbs in a 5 gallon. And also you are mixing many freshwater fish with saltwater. did you even cycle the tank. I would have waited 2 weeks for this tank to cycle because of its size. Do you have a filter. Do you have hiding places ? your fish tank is overstocked already. Your fish took over the carbon and whatever filter media you have. So basically your fish are dying from overstocking and adding too many fish at the same time. Let them float before you put them in. Also I recommend http://www.fishlore.com/ You should check fish before you add them because not all fish come out to be the same size.

Well, you really did not allow the tank to cycle, I know the ammonia was low, but there still needs to be good bacteria to create a good enviroment...

So here are some other guesses? Did you clean the tank? If you used soap at all to pre clean the tanks, that will kill your fish,even if you thought you got most of the soap out. Anyway, you do need to rinse the tank really good, and wipe the edges (no soap) to make sure there are no bad bacteria and stuff. If possible, also sterilize all the fake plants and rocks...

Another guess... did you get some tank decorations? fish need some rocks and stuff to feel at home, else they get too stressed.

But... my best guess is that one of the fish was sick...and then they all got it... I would empty out all the water and try again. Also, go slow, and do not add so many fish so fast.

hope this helps

simple, you havent allowed your tank to cycle. your test kit can't be right. also you have over stocked your tank. you introduced too many fish at one time and well you've just wasted alot of money. go on google and check the nitrogen cycle and then if you have another tank that you could put some fish in that you've had for a while then great.

you need to let you tank cycle