Oscar Died. What did I do Wrong?

[Zak03]

If your friend has had the carbon bags in his tank for a fe months, it will be colonized by bacteria, and putting the bags in your tank, could help your situation.
If your friend has had any major diseases in his tank throughout that time, it may pose a risk to your already weakened fish, although probably no worse than the ammonia toxicity you have at the moment.

he has an oranda goldfish in that tank. its been there for a bit over a month now. and everything in his tank his great. fish look great, none have died, and even some sword tails breeded a bit. but like few days ago the oranda developed a white spot on the top tip of one of its tails. i have no idea if its some sort of fungal disease or not, but we cant help but worry if it's something bad cause we kinda enjoy having that oranda around. would that be cause for not using cycled media from his tank?

 

[jaws7777]

Alright. So I purchased two baby Oscars (red and tiger) from Petco a little bit over a week ago. They live in a 40-gallon tank ( i will upgrade later, don't worry) with two baby sun catfish and two baby common plecos (which I added today). I apologize in advance for the amount of reading you guys will have to do, but I don't know what info I need to include and what I don't, so imma just add a lot of info.

My tank is not fully cycled, but I don't think that's why my Tiger Oscar died. Before two days ago, I only had my two Oscars and the catfish in the tank. Then, two days ago, I added the second baby sun cat to keep the first one company. as soon as I released the cat into the tank, the two Oscars began to harass it. so I removed them and put them into a quarantine tank. after about 40 minutes, I put the Oscars back into their original tank. They didn't harass the new cat anymore. but they got really moody. like really sad; they sulked. so I did some research.

I read here on MFK that Oscars can get moody/sad when they're moved from tanks, tank decor is rearranged, etc. so I figured they'd be okay the next day. yesterday I woke up, and my red oscar was swimming throughout the tank, but the tiger oscar wasn't. I figured to give him some time. later on, I tried to feed my Oscars. (note: I have been having feeding problems, finding the correct food they like. I figured out that they liked sinking pellets, but I had floating pellets. so I bought some when I purchased my second cat). And the Red Oscar finally ate. The Tiger Oscar didn't eat cause he was hiding this whole time.

This went on the whole day. He barely moved all day. I figured he would be back to normal the next day (today). When I went to bed, I turned off the lights and turned on the moonlights. After some time, the Tiger Oscar eventually came out and moved about just a bit. but not much. This morning, I woke up to my Tiger Oscar laying on the tank floor. Dead. So I went and bought a replacement Oscar and the two plecos.

So my question is, why did it die? My other fish, Red Oscar and one of the Sun Cats, have been in the tank just as long and a bit longer respectively. But they're in great shape. What caused it to die? I want to know what to do make sure the rest of my fish don't die.

You've gotten lots of great advice so far. The only thing i will add is if you want to speed the cycling up and save your remaining fish purchase some tetra safestart plus. It will have the tank cycled in as little as a week. Follow the instructions. Should be available on amazon. Id pick up two bottles of the larger size.

Shake like crazy then dose. Do not do any water changes or add a dechlorinator for a week or so. Continue testing the water. If needed add a second dose. The important thing is to not add dechlorinator for a few days after each dose. Also feed very very lightly.

Good luck

 

[jaws7777]

Not sure if its been mention but do you have a test kit ?

I can personally attest to the tetra safestart working like a charm. Ive used it to set up new tanks. To help speed up partially cycled tanks as well. The best part is that nitrite was never detected during the cycling.

 

[duanes]

My own personal rule is a minimum of 2 months quarantine before new fish go into the main tank (I always have a quarantine tank running and cycled). This may seem anal to some, but my own mistakes over many decades of fish keeping have taught me to be careful.
As you can see by your friend Oranda, the white lesion took a month to show up (could have been latent, maybe not).
Many fish diseases look similar, some that look like fungus may be bacterial (white and fuzzy like columnaris), extremely lethal), and these bacterial diseases are very hard and expensive to treat, with the use of proper antibiotics.

The first experiences and learning the ropes of fish keeping are often the most difficult, and get easier after the tank is cycled.
Don't get discouraged, by a few deaths.
In my aquarium club there was a saying, if you haven't killed lots of fish, you haven't been trying hard enough.

 

[neutrino]

If your friend has had the carbon bags in his tank for a fe months, it will be colonized by bacteria, and putting the bags in your tank, could help your situation.

+1

Most people think of carbon as chemical, not bio media, but the fact is any solid surface that gets oxygen, water flow, and is left alone (not cleaned by plecos, for example) can be colonized by beneficial bacteria. I once did an experiment with carbon as my bio-media in a small tank and filter and it worked just fine, main difference is it breaks down over time compared to conventional bio-media.

Gravel in a tank can also harbor beneficial bacteria, I've jumped started more than one tank with a mesh bag of gravel from an established tank placed in a filter to help seed the rest of the filter media. Actually, old school used to be to use your gravel as your filter.

Essentially, the point is there are options, haven't used Tetra SafeStart myself, but I've seen positive reviews.

 

[neutrino]

The first experiences and learning the ropes of fish keeping are often the most difficult, and get easier after the tank is cycled.
Don't get discouraged, by a few deaths.
In my aquarium club there was a saying, if you haven't killed lots of fish, you haven't been trying hard enough.

My personal version of that is fishkeeping isn't always for the faint of heart.

But, yeah, sooner or later we all have our mishaps.