10 gallon - 1 fish died..

[Nelo]

I am extremely sad to report that one of my Julii corycats died over the weekend I bought a trio from Petco on the 10th. I left town on the 11th and came back today to find one of them laying lifeless on top of a little cave I have for them. Being the sensitive soul that I am I cried for a bit and vowed to do what it takes to correct my errors..

I tested my water using my API master test kit.
Ammonia 0.25 ppm
Nitrite 0 ppm
Nitrate 0 ppm
pH 8.2 (I think this is due to the hard water College Station has. Any suggestions?)

I had done a 25% water change on Wednesday, and today I did about a 40-50% change. My tank has been running for over a week now, and I thought it was ok to add fish since my test results were ok earlier in the week..
Today I also removed some moneywort plant that were looking pretty drab.

My other two corys look fine and are acting normal. Oddly enough my Betta fish is the one not quite acting himself. I noticed after I came back over the weekend one of his pectoral fins looks torn, and he is also spending time in the cave which I haven't seen him do as he usually zips around the tank swimming through the plants happily. I made sure to only buy a smooth decoration, the rest of my tank is live plants. The corys don't mess with him at all. I'm really worried about him.

Edit: When my betta, Brock, comes out of the cave for a bit, I see him gasp a couple times. I have the Topfin 10 gallon starter kit and I am using Aquasafe to condition my tap water. I feel like I overfed in the first week, so today I only fed him two flakes.

 

[azmodan]

Hi! Sorry about your cory!

It sounds like your tank isn't cycled.

Guide to Starting a Freshwater Aquarium - Aquarium Advice

I just learned about cycling but I already have fish. What now?! - Aquarium Advice

Check these links and see if that's the case. Best of luck!

 

[Nelo]

I feel like a cruel idiot because I read those articles even before putting fish in, yet I went ahead and started with a betta then I got so anxious to put fish in that I went ahead and got the cories..
I'm afraid my betta looks like he isn't going to last much longer

 

[azmodan]

Don't worry, we've all been there and made similar mistakes. There's actually nothing wrong with doing a fish-in cycle as long as you can keep up with the water changes to keep your parameters safe for your fish. The best thing you can do now is start testing your water daily or bi-daily and doing the necessary PWCs to keep ammonia and nitrites under .25. It may require 50% water changes twice a day and just make sure the water you're adding is conditioned and temperature-matched. You can do it!