Hi! I'm new here, and I'm really in need of some advice, because I'm about to lose my mind.
I've only been keeping an aquarium for about a year, but it's very addictive. I started out with a 5 gallon tank (a big mistake, I learned rather quickly), but I now have a 10 gallon tank, 25 gallon tank, and a 3 gallon tank with my betta fish in it. My little sister got the old 5 gallon tank and put a betta in it. My frustration today (and for the past few months) is over my 25 gallon tank.
I set it up back around late March and was a good girl and restrained myself from adding fish for an entire week to cycle the tank. Since it was in the living room, I let my two sisters help in choosing the fish that would be stocked in it. We stocked it with a few mollies and platys, if I recall correctly.
I've tried all sorts of fish in this tank since then (mollies, platys, swordtails, tiger barbs, gourami, albino corycats), and no matter what, they die. I check the water levels (I have a API master kit), perhaps not as often as I should, but whenever I do, they're fine, even if I just had a fish die. Some lived for a two or three months, but lately almost everything I put in there dies well within the two week warranty the pet store has on the fish. My rainbow fish and my newest golden gourami (the first one died a couple of weeks ago) are the only ones who have made it through the 14 day warranty recently.
I just had an albino corycat and a lyretail silver molly die today. My other albino corycat isn't looking well. I have one platy that I can't find. The other inhabitants of this tank are the following: 2 platys, 2 female mollies, 1 golden gourami, and 1 Lake Katubu rainbowfish.
There are only a couple of things I can think of that might be killing these fish other than some mysterious disease (they have no physical signs of disease even at death). One is that I have two decorations that are hooked up to an air pump, so the water is agitated at all times. The other is that I think we might have been adding too much aquarium salt to the water (my youngest sister helps with the tank. She is 12, and is unfortunately not the most mathematically inclined individual and doesn't quite understand the concepts of water/chemical ratios, etc quite yet.)
Another thing that I should mention is that I've been having a terrible time keeping plants alive in this tank as well. I've had wonderful experiences with plants from the same PetSmart that I buy them from (they're all the same brand there) in my 10 gallon tank--that tank is a beautiful example of how the smallest sized plants they offer there can grow and flourish. But in the 25 gallon tank, I've had the exact opposite results.
I will also mention that our water is very hard in this area and has a very high pH (8.2). The PetSmart I buy my fish and plants from is within walking distance (my apartment complex is literately behind them) so I know they have the exact same water supply as I do. I have attempted to use a faucet purifier for the aquarium water, but it has made no difference to the pH according to my master kit's results, and the test strips the pet store uses showed that the hardness hadn't changed either.
Inhabitants: 3 platys (one is MIA), 1 golden gourami, 1 Lake Katubu rainbowfish, 2 female dalmation mollies.
Size: 25 gallons
Filtration: Marineland Penguin 150B (with two cartridges) and Tetra Whisper 10I
Ammonia: 0 ppm
Nitrites: 0 ppm
Nitrates: 5 ppm
Temperature: 78 F
Thank you so much, and I really look forward to posting here in the future! Hopefully about a tank that's doing well!