Should I euthanize my fish or is there anything else I can do?

Question

I have a betta that I bought a week ago from a pet store. I bought some neon tetras at the same time. I put them in the tank so they could get used to it and be comfortable and kept the betta in the little jar he came in, floating in the ten gallon. I dumped most of the water in his jar out and refilled it with tank water once a day. After 5 or 6 days I netted the betta and put him in.
He seemed happy and healthy enough, exploring his new home, swimming through the plants and under the slate rock cave and eating whatever I put in the tank (except the freeze dried bloodworms). I fed him tubifex worms and regular tropical fish flakes.
Now, around 2 days after I put him in the tank, something bad has happened to him: I checked the tank this evening to see how the fish were doing and the betta was on the bottom, with his body almost vertical- just sitting there with his head up high. I looked closer and saw a piece of his fin had come off. His fins were disintegrating (see more details)

- they were dissolving near the base, not at the tips of, I think, his anal fins. He also had a huge spot that covered a big part of his body and some of his fins. It's a really round spot, not one that's all over the place. His body where the spot is is a dark gray while the fins are reddish where the spot is.
I didn't want whatever he has to infect my other fish (three baby corydoras aeneus, six baby neon tetras, and two otocinclus), so I scooped him out and he's back in his jar with some of the tank water in it.
He's just lying on the bottom, and it seems like he's breathing hard. Not fast hard, but.. struggling hard.
I think he might have fin rot and body rot, although I thought that took awhile so set in. He did not have the spot this morning. I repeat- he was spotless this morning when I looked at and fed him.
Should I euthanize him or is there a remedy? I can't afford a lot right now, as far as antibiotics go.
I just got this little guy and I don't want him to suffer.

Oh and I suppose I should give some specifics:
I have a flourescent light bulb I usually keep on 10 hours a day, but recently I've been leaving them on a few hours longer to promote algae growth for my otos, my tank is fully cycled, and I have been slowly adding fish so there isn't a mini cycle going on. I haven't done a water change for two weeks, but I didn't think that would be a problem given the advice of many websites. Correct me if I'm wrong, please. There's a whisper power filter in there that's the right size. My pH, last time I checked, was right around 7, my ammonia and nitrites were 0 last time I checked- 1 week ago. Temp is high 70s, low 80s (usually around 78, but it fluctuates).

My betta is blue.

Answer 1

Ammonia can be responsible for most of what you are seeing with your fish, but the single large round spot concerns me greatly. Ammonia will cause a much more uniform level of damage not focused in one place.

First and foremost, change 50% of the water in your tank. This will lower the ammonia level and prevent further ammonia damage. If you don't have an ammonia test kit I would recommend you get one to keep track of the ammonia levels as the tank cycles (more on that in a link at the bottom).

The large round spot sounds very much like columnaris. That's a bacteria disease that often appears like a fungus, whitish and cottony looking, but can grow without this cottony look as well. One thing that is consistant to columnaris infections is that it always appears in a round circle, just as you describe. I would suggest you treat the entire tank with a good antibiotic such as Maracyn TC. That will clear the infection and prevent further spread of the disease. Once the treatment is complete, you can cycle your tank and the fish should settle right in comfortable and happy.

For information on cycling a tank, what hat means and what happens, see this page:

http://www.firsttankguide.net/cycle.php

Hope that helps

MM

Answer 2

you have some funky bacteria something going on -- i just had weird stuff go on in mine -- to get my betta better i did a 50% water change and started dosing with maracyn. follow up 25% water changes every 2 days or so.

your water parameters can be fine but bacteria can go crazy in your tank really easily. you have to keep up water changes to keep bacteria changes low and watch for signs from your betta -- and be ready to change water if you see anything wrong.

oh -- and i had some funky funky stuff living in my filter -- so make sure you take it apart and wash it out really good too.

Answer 3

Change the water. New tank syndrome. Most likely high ammonia. Cut back on feeding you may be fouling the water with too much food.

Answer 4

he got stressed probably from his bacterial floral surroundings being changed, it happens. you can bury him in a plant, or in a garden or ground somewhere. fish do make great fertilizer. once a fish reaches that point of deteriorating, they dont come back.

Answer 5

wow let him be what ever happens happens!